Conclusion

Leadtek’s WinFast PX6600 GT TDH SLI kit consists of two WinFast PX6600 GT TDH graphics cards which are identical to the standalone card we described in a separate review. And these two cards too deserve our praises for their quiet and efficient cooling system, good accessories and high image quality.

But when it comes to performance, the results of our today’s tests once again prove that NVIDIA’s SLI technology is not appropriate for mainstream graphics cards. The Leadtek kit is really good in some tests, but is slower than the GeForce 6800 Ultra/GT and RADEON X850 XT in others, especially when you enable full-screen anti-aliasing and anisotropic filtering. The reasons are obvious: the small amount of graphics memory (only 128 megabytes) and the lower efficiency of the two 128-bit memory buses against the single 256-bit bus of the GeForce 6800 Ultra/GT and RADEON X850 XT.

Beside the high price on the SLI kit proper, the multi-GPU technology also requires a not-very-cheap SLI-ready mainboard with two PCI Express x16 slots. Of course, buying a Leadtek SLI kit, you are guaranteed to have no compatibility problems, but you will be limited with 128 megabytes of graphics memory (this is already not enough for many latest games), while the performance in high resolutions will often be less than that of a single top-end graphics card. Yes, you can play in low resolutions and without full-screen anti-aliasing, but it would make no sense ?why pay more if you still cannot use the quality-enhancing features and play with comfort?

Yet another problem with SLI is that you don’t get a performance gain from adding a second card in some games, while a GeForce 6800 GT or a RADEON X800 XL will always give you their maximum performance. The stability of the dual-chip solution is also lower than that of the single-chip card ?you may have image artifacts in some games with certain driver versions in the multi-GPU mode.

That said, we do not recommend you to buy a multi-GPU SLI kit consisting of two GeForce 6600 GT cards. We think a single GeForce 6800 GT or Ultra or RADEON X850 XT/RADEON X800 XL will be a better choice since these cards will let you enjoy comfortable and trouble-free play even with enabled full-screen anti-aliasing and anisotropic filtering.

Highs:

• SLI compatibility guaranteed
• Quiet operation
• Low heat dissipation
• No additional power necessary
• Shader Model 3.0
• Floating-point color representation
• Second-generation PureVideo processor

Lows:

• Small graphics memory size (128MB)
• Performance degenerates in FSAA modes
• Can’t deliver the maximum performance in some games
• Low overclockability