Serious Sam 2
Serious Sam 2 is a pretty demanding game, however despite this fact, all multi-GPU systems perform quite fast in standard resolutions in FSAA 4x mode. In 1920x1200 only GeForce 7900 quad SLI shows acceptable results. But in 2560x1600 the obtained results can only be interesting from the theoretical prospective. In particular, these results show that Quad SLI system suffers from insufficient memory bandwidth, because it is just a tiny bit ahead of Radeon X1900 XT CrossFire – no more than 10%-12%. The latter has to work in not very favorable conditions, because the game is rich in pixel shaders sending a lot of texturing requests. The average number of shader samples is 4, but sometimes it may reach 7-8.
In 1600x1200 with FSAA 8x enabled only GeForce 7900 quad SLI manages to retain nearly comfortable performance level, while the dual-GP solutions fall about 36% behind. In higher resolutions even the quad SLI cannot provide acceptable performance results of about 55-6-fps. So, if your monitor supports 1920x1200, you will still have to play in lower resolution or switch to FSAA 4x.
This test mode is a stumbling stone for all multi-GPU systems, however GeForce 7900 quad SLI and Radeon X1900 XT CrossFire perform almost equally fast in 1600x1200 and 1920x1200. It proves once again that quad SLI system will suffer from insufficient memory bandwidth.
Of course, you shouldn’t even dream of playing in SLI AA 32x mode: the average performance will reach 30fps at best. Besides, Quad SLI platform simply refused to work in any resolution higher than 1600x1200: the system would inevitably crash.