There is in fact no difference between the GeForce 7900 GT and GeForce 7800 GTX on the rather large-scale Pier map even when we compare the corresponding SLI configurations in extreme FSAA modes. The memory subsystem load must be not very high and it is the pixel processors that become a bottleneck here – and there is a mere 20MHz of difference between the GPU frequencies of the two graphics cards. The Radeon X1800 XT leaves no chance to the GeForce 7900 GT, but Nvidia doesn’t mean its $299 product to compete against this monster from ATI. The GeForce 7900 GT is indeed quite competitive against the slower Radeon X1800 XL.
We’ve got the same results on the Research map, but the Radeon X1800 XT doesn’t look as superior as it has been in the previous test, at least when we analyze its single-card performance.
The performance of the GeForce 7900 GT SLI is high enough for you to use SLI AA, but you’ll have to limit yourself to 1024x768 at 16x SLI AA. At 8x SLI AA, all the resolutions seem to be playable.
Far Cry ’s HDR support for ATI’s graphics cards isn’t yet optimized. That’s why the Radeon X1800 XT is far slower than the GeForce 7900 GT. The GeForce 7800 GTX 512 outperforms the GeForce 7900 GT SLI and GeForce 7800 GTX SLI and turns in the best result here.
This is true for both the demos we use in our tests. Note also the lower efficiency of SLI in comparison with CrossFire whose scalability is better in the HDR mode. In the HDR-less game mode, Nvidia’s multi-GPU technology works fine.