SLI PhysX Performance
While the title of this page is SLI PhysX performance, we’ve actually got to admit that we didn’t run the GeForce cards in SLI mode when testing PhysX, instead we relied on the multi-GPU mode. NVIDIA actually recommends that gamers with dual-GPUs run in the multi-GPU mode, with one card dedicated for graphics and the second running solely physics. Based on this, we’re technically not running SLI; SLI must be disabled in the ForceWare control panel in order to run PhysX in multi-GPU mode.
To see how the various GeForce cards perform in this mode, we’ve gathered four different multi-GPU setups: one with two GeForce GTX 280 cards, a second with two GeForce 9800 GTX’s, and the third with dual 9600 GTs. Finally we included a mix and match setup which paired one GeForce 8800 GT with a 9600 GT, with the 8800 GT handling graphics work and the 9600 GT tackling physics:
The dual GeForce GTX 280 rig is completely CPU bound in all our tests. As a result, the 2xGeForce 9800 GTX config is able to match the GTX 280s in performance. Due to time constraints (we’ve had the PhysX driver for only 5 days) we didn’t get a chance to try the GTX 280s in a more real-world scenario with higher resolutions and AA/AF. In this environment the GTX 280s would likely pull a little further away from the other testbeds.
With the exception of MKZ, the multi-GPU results looked very promising: performance is basically on par with dual GeForce 9800 GTX’s at a lower cost.