An alternative technology that allows you to combine two video cards to increase performance is called . Compared with NVIDIA SLI technology, the there are a number of fundamental differences and advantages.
Recall that the technology NVIDIA SLI has several limitations: both cards must be absolutely identical, or in other words, have the same BIOS (although the requirement for identical BIOS was only in the first implementations nVIDIA technologies SLI). In addition, the SLI mode does not work with all games, and if it works, in some cases it does not give the desired performance gain. In addition, the effectiveness of NVIDIA SLI technology and the list of supported games depend largely on the video driver used.
The following pictures show which filters can perform in the processing of all parts of the scene in more detail. Incompatibility for parallel processing when using different plates. . Hybridization is precisely the use of two technologies, which can be interesting in a number of cases.
Thus, the user can install a high-performance card and intermediate card. Here, the same function used in the "Scissors" mode is used, and the task separation will be calculated in accordance with installed models plates.
Technologies of combining video cards (ATI CrossFire technology)
ATI Technology CrossFire works with all games under DirectX and OpenGL. Unified video cards do not have to be the same and can be produced by different companies. Technology ATI CrossFire implies more rendering modes than NVIDIA SLI, and supports the image quality improvement mode.
Using two cards, you can double the speed of the games, because at the same time one frame is displayed on one card, and the next one is displayed. In this case, the user notices a significant improvement in the impacts and other problems existing in the games. The following images display only those filters that can be used to process all the details of the scene in more detail.
Ability to use different models the same series. . When the technology is activated, the computer starts constantly monitoring the use of the cards and checks when it can turn off the power to save energy. When used in games, the quality and performance are not reduced, since the computer takes advantage of the two boards and achieves a minimum gain, which may be enough to release an intermediate board.
At first glance, CrossFire has a lot in common with NVIDIA SLI: for crossFire requires a motherboard with two PCI Express x16 slots under the graphics. Although CrossFire is theoretically independent of the chipset, ATI claims that the system will only work on motherboards with the Radeon Xpress 200 CrossFire chipset.
CrossFire version is slightly different from the usual ATI carg. To build the CrossFire system, in addition to the standard Radeon X800 or X850 (slave / slave) graphics card, a special version of the Radeon X800 or X850 CrossFire video card (master / master) is required. At the same time, video cards are not connected with each other by a bridge - only with a special external cable.
First of all, it's important to check the configuration that you are going to configure. The compatibility list between the boards can be seen from this link. It is worth noting that the boards can be from different manufacturers, but the graphics chip must be identical. Some other relationships should be taken before the purchase of plaques.
None of the technologies will have a 100 percent benefit, in fact, it is likely that in many cases even 50% is not achieved. Just for the sake of curiosity, the frame rate can be even lower than in a situation where only one card is installed. This is due to the fact that not everything depends on the equipment, and some applications are not adapted to use these technologies.
A special chip on the leading CrossFire-card mixes images generated by the usual and CrossFire-card, and then displays the image on the display. Mixing occurs per-pixel.
Separation into a simple and CrossFire version of cards at first glance can be regarded as a disadvantage compared to SLI, since in the case of the NVIDIA solution you do not need to think which card to take, both of the same. But if you think about it, the ATI concept has certain advantages.
Providing high performance
Do you already have this configuration? Available free of charge, it has a combination of high-quality graphics, simple history and good gameplay, but the game can not be played offline. The game has several servers. Recently, the game went with new graphics, modes and characters.
In addition, the game has periodic events, such as the "Wheel of Fortune", which award prizes to participating players. The plot places two self-serving factions - the Black List and the Global Risk - for competition for territory in different regions. Matches support up to 16 people who must work together to win.
Owners of Radeon X800 or X850 can easily buy any CrossFire model to their system. There is no difference in clock speeds, in BIOS versions, in the pipeline configuration, or in the manufacturers. The only limitation is that the CrossFire model must match another graphics card. In other words, be a card X800 or X850.
Each game mode has its own specific maps and rules. Check each of them below
The team that wins the highest score at the end of the term wins. Search and destroy: one team attacks and the other defends the territory. If a bomb is planted, there is a short time for its deactivation by protection. Whenever a player dies, he does not degenerate on the map and must wait for the turn to end. The "Black List" group is invisible and can only use the knife as an attack weapon. Already an enemy group can not be invisible, but can use any weapon.
CrossFire-version of the card coordinates the clock frequencies and adapts to the usual map based on pixel pipelines. For example, if a conventional card uses 12 active pixel pipelines, the CrossFire card will also go to 12 pipelines. But you have to pay for flexibility. Owners of the "younger" X800 or X850 will pay quite a decent amount for the CrossFire version of the card compared to their own, and not the fact that they will get a big win, because the pace of the race will be set by a regular card.
Mercenaries have four different types of characters
He was born to fight against any terrorist activity that could threaten world peace. The game features periodic events, such as the "Wheel of Fortune", which award prizes to participating players. This was an interesting way for developers to figure out how to save the game.
A huge advantage for its players is organized championships that allow anyone, at any level of program development, to be able to fight on an equal footing. Despite the free game, your most desired items are those that can be paid only by real money, which can end up discouraging users.
The ATI CrossFire technology provides four modes of operation:
1. SuperTiling;
2. Scissor;
3. Alternate Frame Rendering (AFR);
4. Super AA.
SuperTiling mode is the standard mode for the technology. It works for all Direct3D games and applications. It should be noted that modern graphics processors do not simultaneously process the whole image - they divide it into small squares (quads), which are decomposed by the processor on different pipelines. In SuperTiling mode, the screen is divided into individual squares of 32x32 pixels in size so that each video card receives an image with staggered fragments for processing. Thus, the load is divided strictly evenly between frames, regardless of the particular scene, but the geometric load has to be duplicated - both cards calculate the same geometric data.
Satisfactory number of obstacles A large arsenal of weapons The wheel even on the base computers of the Mission meet, generate items to be used in matches. Slowness Several additional features Some items are only available for purchase with real money. Differences and similarities in gameplay.
In terms of gameplay, two games look good. But the improvements do not go beyond graphics and more beautiful landscapes. One of the most commendable things in the series has always been its fun and accurate gameplay, so the producer decided to do it very little. In total there are 16 maps, among them 8 classics and 8 completely unpublished. Among the classic maps we have Aztec, dust, dust 2 and inferno.
The advantages of this mode include the ability to work with all games and applications, as well as the optimal load distribution (in terms of pixels). At the same time, in some applications in SuperTiling mode, performance is slightly increased. Both maps must calculate the entire geometry of the scene, even if they then calculate half the pixels. In games that use pixel programs heavily, you can expect higher performance gains. In addition, the SuperTiling mode does not work with OpenGL games.
Not to mention the possible changes, which greatly increases the number of options. In the end, the choice depends on the features that you are looking for in an online game. The rival factions are fighting for influence and power in a ruthless and endless war. The game has servers that spread across several countries, including Brazil. It even offers many unique and unusual combat modes, where you can fight monsters, zombies and "ghost warriors". Click here to create your own account, before you start playing!
Realization of SuperTiling mode
The Scissor rendering mode divides the screen into two parts horizontally. One hag calculates the top of the screen, and the second - the bottom. Dynamic load balancing allows you to divide the screen into parts in such a way that the cards are loaded with an equal computing load. This mode is standard for OpenGL applications. In addition, this mode allows you to get performance gains in most games. In the same time, as in the case of SuperTiling, in Scissor mode, both video cards should completely calculate the geometry of the scene.
There are still many players in almost any room that you enter, which in the end provides many goals and entertainment. The available arsenal is quite extensive and diverse, providing options for any profile of the fighter. You basically use the mouse cursor to direct your character through scripts, in addition to the ability to watch.
To shoot or use any other weapon in your hand, just click left button on the periphery. In training mode, the game explains in detail how to use each of these controls, in addition to several more basic ones. Of course, you can adjust almost everything to make you have more comfort during the game.
ATI CrossFire: mode (AFR)
The Alternate Frame Rendering (AFR) mode involves alternating frame rendering by each GPU. One card calculates all the odd frames, and the second - all the even ones. It is easy to understand if we take into account that the changing scene always consists of a sequence of individual frames that quickly replace each other, creating the impression of continuous movement.
The game developers paid special attention to the number of items in the arsenal. In other genre names, it's difficult to find a variety that can leave you completely indecisive when it comes to shopping in a weapons store and protective equipment.
At your disposal is a collection of firearms, knives, ax and other sharp elements, as well as many grenades; one for each type of person. You can choose a weapon not only for your abilities to kill, but for your style. In addition, with each new update patch, new items appear in this arsenal to make things more interesting.
The advantage of this solution is that both cards optimally distribute the computational load. However, in some cases, the use of AFR mode is impossible: for example, when processing the next frame directly depends on the results of processing the previous one.
The fourth mode of CrossFire is called Super AA (Anti-Aliasing). More precisely, we are talking about not even one, but four modes of Super AA: 8x AA, 10x AA, 12x AA and 14x AA. In these modes, the card does not provide a higher frame rate (performance), but significantly improves picture quality. These modes will improve the quality of the image in games that do not receive a performance gain from using two video cards. The availability of these alternative rendering modes is a key difference in technology from NVIDIA SLI.
There are dozens of rooms and maps to explore, and your character can deal with daily tasks in order to earn as many rewards as possible. In this case, the player can improve his personal arsenal and get into new battles, armed to the teeth. Tasks change every 24 hours, and you have a chance to win something completely new with each of these missions. There are rooms that are completely chaotic, with explosions from all sides, as well as with other extremely tense rooms, where enemies are always in search.
Thus, you create extremely reliable and "professional" teams to get the best prizes in the game. For these clans there is also a national, regional and global classification system. Thus, you can help create the reputation of your group so that its members become the most terrible group in the game. If you want to create specific rooms for more intensive training, you can participate in private battles that are open only to everyone who is invited or has a password.
Super AA modes can be used in all applications without any restrictions, since they do not assume the distribution of the workload between the two video cards - each hag renders the frame based on a unique set of sample points, after which the results of the rendering are combined and a single image is formed.
Thus, you can better control the situation as a whole, without the possibility of encountering any newcomer and eventually dying without the need. In addition to traditional modes, such as solo, campaign, multiplayer game, among others - you have the opportunity to play against unconventional enemies in games of this style. For example, there is a mode in which you encounter very disturbing mutant monsters, with specific missions and differentiated game functions. If you are going to kill some zombies, there is another special mode for this, and you need to kill all the living dead on the map.
In 8x AA mode, both cards generate the same image, each of which works in the 4x image smoothing mode, but uses different sampling points (anti-aliasing patterns). Then the chip mixes both pictures into one. As a result, the user gets 8x anti-aliasing at the price of 4x FSAA.
Similarly, in 12x AA mode, each card works in the 6x image smoothing mode, but uses different templates. As a result of mixing the images, the 12x AA smoothing mode is obtained at a performance corresponding to the 6x FSAA mode.
Read the characteristics of each game mode to know exactly what you will encounter. Also worth recalling are the weekly events that the game is promoting. These are special missions that the developer defines every week. If you participate in these problems and win some of them, you can get items in the game or even virtual money to buy something else. It is worthwhile to follow the "game schedule" and try to participate.
Check the classes available in the game below. Owners of special skills, such as brutal blows, knife throws and perfect maneuverability, vipers make a difference on the battlefield. Also in this sense, the title received repeated formulations in the player interaction interface. Changes redistribute some elements and condense them to make the usability even more intuitive.
In the 10x AA and 14x AA modes, a fundamentally new concept of the SSAA (SuperSampling AA) mode is used. In fact, these smoothing modes are a combination of 8x AA and 12x AA modes with a new technology of smoothing 2x SuperSampling AA, in which each card processes the entire scene with the necessary resolution and a diagonal shift to the ion pixel. As a result, the scene rendering is actually performed in 10x AA mode (8x AA + 2x SSAA) or 14x AA (12x AA + 2x SSAA).
The game now offers two new modes. The first one is "Spy Mode", in which the player has a chance to join the team and, without any title, betray her confidence. Thus, you have the opportunity to choose between destroying opponents or destroying your own team.
Another way is "Arena". There are only two players in a battle at a time. These battles are worth much more than winning, medals and reputation. And they could not miss the new equipment. The update of the game also brought unpublished weapons with special characteristics, not to mention the functions that can improve the soldiers' abilities.
Micro-stuttering and scaling of multiple graphics cards
One video card or more? We are faced with this issue every time we collect a game platform or evaluate the flagship models of video cards.
Which is better: one card, two, three, four? Will several cheap video cards in a bundle show better results in work than one expensive?
The already well-known cooperative mode of the game will receive new functional capabilities, mechanics and, mainly, rewards. It's all worth it: machine guns, pistols, grenades and knives. A total of 24 items, including primary, secondary, armor, accessories and trophies. But ship protection is not an easy task. To help the team in this mission, several defense devices will be available throughout the match.
Zombie mode 0 now occurs on a new map, the Holocaust, a city destroyed by a nuclear catastrophe. The second unpublished map is intended for "Only with only knives": a gladiator based on ancient Roman amphitheatres, with narrow and hanging platforms.
To answer these questions, we are going to conduct tests of the performance of CrossFire and SLI and talk about the results. In addition, we will talk about the basic principles of video cards. After all, the high frame rate, in and of itself, does not yet mean a high quality picture.
Yes, we'll talk about micro-stuttering, an effect that for many users is the reason for not assembling a computer with multiple graphics cards. We will analyze the scaling on two, three and four video cards. Is there any benefit from this and when does the time come when the further increase in the rate of the frame rate becomes useless? There are a lot of factors. Of course, increasing the performance of graphics this way to infinity will be a waste of money; However, the actual work of several cards in a bunch sometimes gives very good results.
What changed?
When testing mid-range video cards, we are faced with a technical problem. AMD and nVidia limit the possibility of expanding mid-range video cards with one bridge. With this series of devices, only two video card configurations are possible. Two bridges that allow you to install bundles of three and four video cards are usually available on expensive devices.
The purchase of two high-end video cards is very expensive. Take, for example, the model PowerColor Radeon HD 6870 X2. This graphics card is equipped with two mid-level graphics processors, which allows you to assemble a configuration of four graphics processors in CrossFire. As a result, we can compare a typical midrange graphics card, similar to the Radeon HD 6870, with a configuration on two graphics processors (Radeon HD 6870 X2), three (connecting another Radeon HD 6870 to the Radeon HD 6870 X2) and four processors.
In addition, we will check for a number of indicators the same configurations of popular graphics cards, up to GeForce GTX 590. Our task is to evaluate the efficiency of configurations, losses with micro-stuttering and, finally, to provide a rating of video cards for key indicators. Are there any surprises waiting for us? It's likely, read on, and you'll find out about it.
How does CrossFire and SLI work?
How load balancing works and what is Alternate-Frame Rendering (AFR)
AFR is the most commonly used technology of joint work of several video cards. As you can understand from the title, the processing of frames is done completely on different maps. For smooth and smooth operation, it is required that the cards are loaded approximately equally, and also that they have identical or similar performance.
The combination of two graphics cards of different performance will lead to deplorable results. The reason is not that in this mode of operation a more powerful card will work slower; this is a very common opinion is incorrect. Simply, the load becomes unbalanced and will lead to malfunctions.
Let's look at the simplified scheme of work of a bundle of two video cards. Card # 1 processes the first frame, in parallel, card # 2 processes the second frame. Next, card number 1 works with the third frame, and card number 2 - with the fourth. The images are transferred to the display via the map buffer No. 1, to which the monitor is connected.
The system works fine until the load on both cards is the same. Even if you use a bundle of two cards, the limitations of buffering and data transfer will be very stringent. The output of graphics is always a problem for such systems.
What is micro-stuttering?
Let's see how the sequences of frames are processed. AT real life an ideal balance is unattainable and the system can not create a work script from, say, 30 frames, so usually we see the following picture:
This is the result of processing a data packet in one second of the gameplay Metro 2033 by a bunch of two video card Radeon HD 6850. We chose this scenario and the equipment, since they give a frame rate of about 30 per second. It is believed that it is with this indicator that the effect of micro-stuttering is particularly noticeable.
According to the graph, there are serious changes in milliseconds per frame when switching from one to the other. The pie chart shows the entire period in one second. As is easy to see, some frames are delayed (stuttering, "stuttering"). And, although the frame rate remains high enough, the effect still makes itself felt.
This can be compared to a similar effect of an automobile engine. You can imagine overclocking a 6-cylinder engine to 30 miles per hour: if one of the cylinders is defective, it will be felt, although the speed will not decrease.
When is the effect of micro-stuttering noticeable?
Always. The action is such that the actual high frame rate will be perceived as low, for example, 30 FPS can be perceived as 20-25 FPS. This is bad, especially if one knows that the human eye is able to notice differences in frames even at 60 FPS.
This is one of the reasons why we prefer to test for higher FPS values. Surprisingly, even with FPS values greater than 40, the effect of micro-stuttering remains noticeable.
Step 1: two video cards in CrossFire
Radeon HD 6870 X2
Using Radeon HD 6870 X2, we get the right configuration: CrossFire on two graphics processors.
Let's see what this video card represents. On its board, there are two graphics processors connected via a bridge, using the Lucidlogix chip.
The first graph shows the performance for Call of Juarez in 1920x1080 resolution when working with Radeon HD 6870 X2. It is immediately evident that the performance when working with two cards is about twice as high. However, it is obvious that the graphics line for the two graphics cards is more choppy.
Although the peak performance for the GPU bundle gives 200% of the performance of one processor, at some points the FPS drops sharply to values just above the platform with a single Radeon HD 6870. Of course, the average FPS increases, but the micro-stuttering effect also appears.
Two cards Radeon HD 6870
Let's compare the performance of the Radeon HD 6870 X2 with a pair of conventional Radeon HD 6870, connected via the CrossFire bridge. The cost of such a bundle will be $ 360 against a dual-chip video card, worth $ 470.
The frame rate, as we see, is comparable, but without the mediation of the Lucidlogic bridge, the performance dips will be slightly less.
Despite the almost imperceptible difference in performance and price dispersion of almost $ 100, the jumping frame rate when running a bundle of two video cards will be a serious argument against, for some users.
So, the only reason to use the PowerColor card is the lack of expansion slots on the regular Radeon HD 6870. Also, the convenience issue may play a role; but this is not a change in performance.
Step 1: two video cards in CrossFire (vs. SLI)
Our review will be incomplete if we do not compare CrossFire from AMD to a competitor - SLI from nVidia.
Unfortunately, we have to limit ourselves to testing cards with average parameters, since we did not have access to dual-chip cards (like EVGA GTX 460 2Win). Thus, we will make a direct comparison of the work of a bundle of Radeon HD 6870 video cards in CrossFire with a bundle of GeForce GTX 560 cards in SLI. Both tested cards, by themselves, have similar parameters.
At first glance it seems that the cards from nVidia do not work very well in SLI. However, the effect of micro-stuttering in their case is less pronounced than the strong braking when working with CrossFire. At the same time, it will not work well for them either: the effect still makes itself felt.
Note that even one GeForce GTX 560 (without Ti) works with a large spread of FPS, despite the almost identical average FPS values.
In Call of Juarez sLI technology not as well scaled as CrossFire, which results in a lower average frame rate compared to the two Radeon HD 6870 in CrossFire. Radeon graphics cards, on the other hand, suffer from a noticeable slowdown, although the slower GeForce pair appears to be subjectively faster due to a decrease in this effect.
We tested the configurations and other indicators. I must say that the advantages of nVidia become more obvious when the driver is optimized for smooth frame switching. The company issues useful applications for optimization and their competent adjustment can give the best performance.
Intermediate output
nVidia is still in the lead, despite the gap in price. In Call of Juarez SLI does not work as well as CrossFire, but it provides a smoother frame change.
Step 2: three graphics cards in CrossFire
The Radeon HD 6870 X2 card plus the usual Radeon HD 6870 - we get a triple bundle in CrossFire.
When using Radeon HD 6870 X2 from PowerColor, we have a bridge for connecting three Barts graphics processors, in spite of the fact that only one bridge connector is available in the Radeon HD 6870. How will this bunch work?
All three devices will cost $ 650, which is $ 80 less than the GeForce GTX 590. Unfortunately, all video cards AMD Radeon HD 6990 on Newegg, Zipzoomfly and TigerDirect are not available for purchase, so we can not evaluate their performance.
However, let's look at the charts.
We repeated the same tests with the same games to measure the results of the frame change. When the FPS value rises above 30, the resulting image can be characterized as smooth. There remain small differences in how the frames get on the screen, but this does not affect the perception: everything looks the same as when using one video card.
Of course, after testing a bundle of two video cards it looks amazing.
Intermediate output
Surprisingly, in CrossFire mode, a bundle of three cards has a huge advantage over a dual system of video cards. In addition, this equipment is cheaper than dual-GPU cards GeForce GTX 590 and Radeon HD 6990. At the same time, the average frame rate is only 20% more than the Radeon HD 6870 X2. Yes, and 420 watts of power consumption - not so small a value, higher except that the overclocked Radeon HD 6990.
Step 2: Four graphics cards in CrossFire (vs. SLI)
Two video cards Radeon HD 6870 X2 give us a bundle of CrossFire of four graphics processors.
Now let's see how the device will work, using four graphics processors at the same time. The cost of two PowerColor cards is about $ 940, but they allow parallel high-speed graphics processing. First, let's compare the triple and quad configurations in CrossFire:
Because of the inflated price for X2 graphics cards, a slight increase in productivity by 15-20% (compared to the previous version) will be very expensive. In addition, with the configuration of four cards in CrossFire, it makes no sense to set the resolution to 1920x1080: in the end, FPS is about 150.
Increasing the resolution to reduce performance will require a larger amount of graphics card memory. One-gigabyte cards are hardly enough to provide a resolution of 2560x1600 on a 30-inch screen or three 24-inch monitors with a working resolution of 5760x1080. In such cases, you should think about a bunch of 2 GB of Radeon HD 6950 video cards.
CrossFire vs. SLI
We tested the GeForce GTX 590 and Radeon HD 6990 possible ways, since we were interested in how they work together. We also wanted to test the performance of the GeForce GTX 590, but did not find another card that would work steadily with it in SLI mode. More details about this are written in the page below.
Here are all the graphs for comparison:
Intermediate output
Surprisingly, most people for some reason prefer triple bundles of expensive cards from AMD video card GeForce GTX 590 from nVidia. The higher frame rate and minimization of the micro-stuttering effect look amazing and inspiring. And this explains why AMD does not now put the second CrossFire connector on the video card data; such a move would lead to the failure of sales of more expensive devices of this company.
However, early for optimistic conclusions. The fact is that when installing drivers for video cards from AMD there is a big risk to face incompatibility problems. The triple bunch in CrossFire worked well in most games and tests. However, problems with drivers can in some cases reduce its performance to the level of dual-chip devices. And then the only advantage of the triple bundle in CrossFire will be the best indicator of the frame rate.
The Radeon HD 6990 is not much faster than the Radeon HD 6870 X2. If you take into account all the factors, then the only advantage of this card will be the lack of the micro-stuttering effect, which is observed when double-link video cards work. However, this factor also fades away if we use three video cards.
Now we can look at the remaining test results and find the configuration, in which the micro-stuttering effect will be minimized.
Test configuration and programs for testing
| Test system | |
| CPU | Intel Core i5-2500K @ 5 GHz for verifying processor scaling |
| Cooler | Prolimatech SuperMega + Noiseblocker Multiframe PWM |
| Motherboard | Gigabyte Z68X-UD7 |
| RAM | 8 GB Kingston HyperX 1600 "Genesis" |
| System hard disk | 256 GB Samsung 470 Series |
| Power Supply | Cougar GX 1050 80 PLUS Gold |
| operating system | Windows 7 x64 Ultimate |
| Test equipment | |
| Measurement of power supply | Energy Logger 4000 (Conrad Electronic) Voltcraft SBC-500 (Conrad Electronic) |
| Measuring the noise level | Voltcraft SL-400 (Conrad Electronic) |
| Synthetic tests | |
| 3DMark 11 | Grahpics Tests 1-4 |
| Unigine Sanctuary v.2.4 | Dynamic lights HDR rendering Parallax occlusion mapping Ambient occlusion mapping Translucence Volumetric light and fog Particle systems Postprocessing Interactive experience with fly-through mode |
| Game Tests | |
| DirectX 11 | Metro 2033 Aliens Vs. Predator |
| DirectX 10 | Call of Juarez |
| DirectX 9 | Mafia II |
The range of settings and permissions under which we ran various applications during testing is traditionally wide. However (taking into account also the cost of components), we can distinguish two general categories of performance. For the "gamer" category we accept working permit screen 1680х1050, and for the category "enthusiast" - 1920х1080. In accordance with these two categories, the image quality settings are also displayed.
Performance index and calculation method
We refused to use the indicator of the total frame rate. Instead, the indicator of the frame rate of video cards in our study receives different estimates for the two highlighted categories. So, if the video card is ranked low in the column "gamer", this does not mean that in the column "enthusiast" its indicators will also be low. If we took aggregate values, then it would be difficult to evaluate the effectiveness of a particular video card under specific conditions.
For testing, we needed one device of conditional higher and conditional middle classes from each manufacturer. This, respectively, Radeon HD 6970 and Radeon HD 6870 from AMD, as well as GeForce GTX 570 and GeForce GTX 560 Ti from nVidia. We tested these video cards in 15 different games. Then we create the artificial third group "Raforce Gedeon", whose indicators are calculated as average for pairs of cards of each price category. This third group is necessary for us as a reference for the settings in each of the tests. Its FPS is taken as 100% for each of the categories in our tests. The two final indexes are obtained by dividing all the performance indicators (in percent) by the number of tests. Thus, we level the advantage of optimizing a device for a manufacturer. It only seems complicated, in fact everything is simple. For the usual gaming settings, our testing data will be a good criterion for estimating the price-quality ratio.
Power consumption and temperature measurement
We provided full CPU utilization with Prime95, which runs processes in the background. Then we measured the energy consumption of all video cards from the initial level, the power consumption characteristics of which are known. The measurement was made in idle mode and with FurMark running. Subtracting the known energy consumption values for video cards from the total power consumption, we obtained the energy consumption figures for the entire system without a video card. Two of these values are almost identical, so we just subtracted 131 watts from all subsequent measurements of the system's power consumption to get the power consumption of the video card. For the control check, we also analyze the overall power consumption of the system.
Test results
3DMark 11
Unigine Sanctuary
Intermediate output
In both tests, bundles from several video cards perform superbly. However, it should be noted that the developers of drivers for each company have made great efforts to give the maximum performance in these tests. If real games were going on as easily as synthetic tests show, we would not have done this research.
Metro 2033
Aliens vs. Predator
Intermediate output
It seems that the latest driver package from AMD is unstable and this affects performance. In order to get adequate data, we use the old version of the driver when launching Metro 2033.
Neither NVIDIA nor AMD managed to avoid the effect of micro-stuttering in the mode of several cards. A good result in this respect is shown only by the coupling of three cards in CrossFire.
AvP gives AMD devices a noticeable advantage over the frame rate. However, they are equally susceptible to the effect of micro-stuttering. A bunch of three or four graphics processors is needed in order to get the level of smoothness of the image that SLI gives from Nvidia.
S.T.A.L.K.E.R .: Call of Pripyat
Call of Juarez
Intermediate output
S.T.A.L.K.E.R. works better with AMD cards in high-resolution modes and with the maximum settings. The effect of micro-stuttering worsens the picture both on AMD cards and on nVidia cards.
When you start Call of Juarez, this effect is even more noticeable. Although at high load CrossFire provides good scaling, the vulnerability to micro-stuttering remains strong.
Let's draw conclusions on the work of GeForce GTX 590. It should be recognized that all configurations, except for bundles of three and four video cards in CrossFire, do not give impressive results. The cards from nVidia cope better.
Mafia II
Intermediate output
When we launch Mafia II, we see a strange picture. At low resolution and image settings, AMD gives better results than nVidia, however in the category of "enthusiast" nVidia is knocked out by the leaders.
However, in both cases we observe the effect of micro-stuttering. In high resolution, nVidia gives worse results than AMD. The best results for the parameter micro-stuttering give a triple bundle in CrossFire.
Performance index
Intermediate output
If we recall what was said in the introduction to this article, then when looking at the results of our tests it becomes clear that most of the records have only theoretical value. In practice, these numbers will in some cases mean that the effect of micro-stuttering will not be manifested, and the picture will be perceived at the level of the average frame rate.
Bundles of three and four video cards based on CrossFire demonstrate the best performance in our charts, as their performance is not degraded by the effect of micro-stuttering. However, configurations with two video cards are much more susceptible to the effect of this effect and, depending on the game, can show more or less good results.
Energy consumption
For someone, record indicators of the frequency of personnel change are the most important indicator. Such users do not care how much money it takes to leave and electricity bills are not important.
The last phrase could be the motto of our today's experiment. Test configurations can not be called energy efficient. And the situation only worsens with the addition of new devices in the working configuration.
If you still want to take into account the energy-saving indicators, the simplest solution will be a three-card configuration on Barts from AMD. They are 100 watts more economical than the GeForce GTX 570 and at the same time give higher performance, which can not be praised.
We also note a very high energy consumption of a bundle of two video card GeForce GTX 580. This is the bottom line in the diagram.
CrossFire, SLI and micro-stuttering
Drivers or equipment?
In order to get the best possible result, it is often fairly true to establish the required driver. And if installing the driver for a single video card is a simple and routine operation, then when you connect a bundle of several cards you will need a lot of patience.
For example, many difficulties will arise when trying to connect through SLI a bunch of two video card nVidia from different suppliers. That's how it was with us. Of the six available GeForce GTX 580 graphics cards, only two worked steadily together in all tests. Of the five available GeForce GTX 570 - only three. The resulting problems affect clock speeds, BIOS, platform support, and so on.
The equipment from AMD behaves better when it comes to compatibility with games. However, AMD also loses its advantages when trying to assemble a configuration from video cards with two chips on each in CrossFire. We several times ran into failure. In addition, certain inconvenience is caused by the fact that CrossFire configuration profiles are not available for modifications. So, if you decide to connect more than one video card to the workstation, be ready to spend time solving the problems that may arise.
Two video cards in CrossFire
If the main criterion is the average frame rate, then installing two video cards will not be justifiable in terms of finance. In addition, according to the opinions expressed by our readers in the letters, the effect of micro-stuttering greatly hinders the work.
Even with a FPS value of 50 or more, the problem of micro-stuttering remains relevant, significantly worsening the gameplay. So we do not recommend buying an inexpensive video card in order to later expand its second one. At least until AMD and nVidia take action to eliminate the effect of micro-stuttering. In this case, the achieved improvement in productivity will simply be leveled. Today, even using cards with more power than the Radeon HD 6950 will not solve this problem. Even if you can get a high FPS, the mirco-stuttering effect will be clearly visible during the game.
However, the problems with changing frames do not equally affect different equipment, and there are many TFT LCD displays that can hide the effect of micro-stuttering. In addition, for some, this problem may not be fundamental at all. But anyway, AMD company should make efforts in the direction of supporting the work of bundles of two video cards.
Three and four video cards in CrossFire
Working with configurations of three and four cards clearly indicates that the effect of micro-stuttering should not be an obstacle if you want to build a platform from several graphics processors. For some reason, adding a third video card practically reduces the effect of micro-stuttering to none; at least, it will no longer affect performance. As for the addition of the fourth device, it is already superfluous: a significant increase in productivity in this way is not achieved.
From possible configurations to the AMD card Radeon HD 6870 with two connectors CrossFire the best the ratio of price and performance will be a triple bunch. Currently, the only way to get this configuration is to connect to the PowerColor Radeon HD 6870 X2 video card HD 6870 with a single chip. The cost of such a solution will be $ 645, which is much cheaper than a comparable GeForce GTX 590 card. Besides, the flagship of nVidia is slightly behind in performance and demonstrates a greater effect of the micro-stuttering effect in operation.
I would like AMD to pay more attention to the possibilities of dual video card configurations. Despite the potential impact on the average frame rate, you can achieve better gameplay and higher performance. A configuration with three graphics processors can be a model in optimization.
SLI
The approach of Nvidia is more consistent, despite some unresolved problems with the effect of micro-stuttering: at least, the video cards of this company work together steadily, as we expected. However, the effect of this effect spoils the overall picture. In essence, spending money on installing several cards (for example, GeForce GTX 550Ti) via SLI is only meaningful if you are interested in individual records for the rate of frame change.
Concluding remarks
So, we did not note any revolutionary changes in terms of FPS and micro-stuttering. Although it is worth mentioning about the improvement of drivers from nVidia. But still: at the moment there is no solution that would ensure 100% smoothness during the gameplay when using two graphics processors simultaneously.
In a situation where sellers are trying to set prices for two mid-end video cards at the same level with high-end solutions of similar characteristics, we should have always bought a single-chip video card. Justified, therefore, is only a configuration with three graphics processors. However, for us, as for consumers, the policy of companies may become an obstacle: it seems that AMD and nVidia intentionally leave medium-price video cards minimal expansion possibilities, which allow to assemble no more configurations than from two video cards. There are other solutions, of which we mention the PowerColor Radeon HD 6870 X2. From its shortcomings it is worth mentioning about the slightly overpriced and high noise level. We can only hope that CrossFire will continue to support such configurations in the future.
Another conclusion from our study: the faster graphics card in a bundle, so with fewer problems you will encounter. Thus, it is hardly worthwhile to engage with each other video cards of the lowest price range. This is justified only for maps of the middle and higher segments. The note is relevant for both CrossFire and SLI (the latter, however, is a bit friendlier to the user). So for fans of budget solutions, assembling configurations from two or more video cards is unlikely to be justified. And one more note in connection with the cost: of course, when choosing from identical devices characteristics and cost, our choice will fall on a device with a single graphics processor. Simply because in this way all risks of incompatibility can be avoided and there is no micro-stuttering effect.
