Conclusion

Recently we benchmarked dual-processor tandems Radeon HD 4890 CrossFireX and GeForce GTX 285 SLI and referred to them as heavyweights. So, this review has been about super heavyweights that feature the combined power of three or even four GPUs. But do such systems make a practical sense or they should only be used for setting speed records in benchmarks? We will sum up this test session and answer the question now.

It is clear that modern multi-GPU solutions are redundant for the resolution of 1280x1024 (they are used for that resolution but rarely, though). There are but few exceptions, particularly the CryEngine 2 based games such as Crysis and Crysis Warhead. In these heavy applications the GeForce GTX 285 3-way SLI subsystem can achieve an average frame rate of 55-60fps and a bottom speed of 29-30fps. Besides that, this advanced and expensive subsystem can be useful for the highly demanding flight sim Tom Clancy’s H.A.W.X. – if you don’t mind the noise it produces.

The resolution of 1680x1050 pixels is somewhat more interesting although we don’t think that people who have inexpensive 20-22-inch monitors will shell out $700-1000 for the graphics subsystem. Crysis Warhead, H.A.W.X., and Mass Effect with forced 4x FSAA are the only games that can utilize the advantages of the 3- and 4-way graphics subsystems. In every other case a single Radeon HD 4890 or GeForce GTX 285 is going to be enough.

The display resolution of 1920x1200 pixels is still rather rare even though there are inexpensive 24-inch TN-based monitors, e.g. Samsung SyncMaster 245B or Acer AL2416W. Users who have 1920x1200 monitors are more likely to be able to afford two or more top-class graphics cards.

Ironically, the 3-way GeForce GTX 285 configuration cannot maintain an acceptable bottom speed at Crysis Warhead. The discrete multi-GPU solutions show their benefits in S.T.A.L.K.E.R.: Clear Sky instead. They ensure a larger reserve of speed than the single GeForce GTX 295. It is hard to name the best solution here but we’d prefer the Radeon HD 4890 3-way CrossFireX due to its better noise characteristics. The same goes for Mass Effect and H.A.W.X.

The resolution of 2560x1600 is the paradise for many devoted gamers because a 30-inch monitor allows for a deeper immersion into the virtual world. It is here that super-fast multi-GPU solutions show their full potential.

The GeForce GTX 285 3-way SLI is not always in the lead at 2560x1600. It wins 9 and loses 6 tests to the Radeon HD 4870 X2 tandem but it is only in four tests (Crysis Warhead, Enemy Territory: Quake Wars, Mass Effect and World in Conflict: Soviet Assault) that the gap is over 15%. Nvidia’s platform has a large advantage (the score is 12 to 3) over the Radeon HD 4890 3-way CrossFireX but the gap is large in five tests only.

Is it so bad for ATI’s solutions, anyway? The difference is insignificant in Crysis Warhead because Nvidia’s 3-way platform cannot deliver acceptable speed, either. In the other tests the Radeon HD 4890 3-way CrossFireX provides a playable frame rate even though being slower than its opponent. Moreover, the Radeon HD 4890 3-way CrossFireX is far more comfortable in terms of noisiness. Delivering high performance at 2560x1600 at a rather comfortable noise and the lowest power consumption in this class, the Radeon HD 4890 3-way CrossFireX looks like the most optimal solution to us. The Radeon HD 4870 X2 4-way CrossFireX is worse because its advantage over the 3-way subsystem based on newer RV790 cores is small whereas its power consumption and noise level are higher.

Winding this review up, we want to say it once again that today’s multi-GPU technologies have a number of fundamental drawbacks that cannot be corrected even theoretically. Modern multi-GPU solutions depend on software support from both game developers and driver programmers. The so-called heterogeneous multi-GPU might save the day, but this concept seems to have been abandoned without making it into hardware implementations. Perhaps DirectX 11 will change something, but it’s yet too early to make any guesses about it. And beside everything else, multi-GPU solutions are clumsy, noisy, power-hungry, and very expensive.

We do think that a buyer who spends over $500 for one graphics card or multiple cards should get maximum performance out of the box, without bothering about versions and settings of the drivers and the availability of SLI/CrossFireX optimizations for his favorite games. Game developers who cannot make good use of the huge resources of modern graphics hardware are to blame, too. The only positive trend is that there are more and more multiplatform projects that have to be optimized for the modest resources of today’s gaming consoles.