Testing
As stated above, our custom testing method of GRAW consisted of tossing three grenades into a big stack of boxes. We saved the game after throwing the first grenade in order to ensure all of our tests started in exactly the same manner. As a result, approximately 3 seconds after our tests start, a grenade blows up in the stack of boxes, causing them to blow up and fly every which direction. This would be what we classify as the “Fidelity” dimension of the test. After the initial scattering of boxes, we threw another grenade into the main pile at 15 seconds into the test. This grenade then exploded at approximately 19-20 seconds into the test. We did the same thing again at 30 seconds, and saw the explosion at about the 34th second. We ran the test without the ASUS PhysX PPU installed first, to get a “control” set of data as it were. FPS was plotted against time with the aid of Fraps. The test duration was held at a constant of 45 seconds from level load. The results of our first tests are displayed graphically below.


You can clearly see that the FPS drops at instances where the grenades exploded and caused the massive physics extravaganza to take place. Also please keep in mind that the first 4 seconds of these results should be disregarded because they occur while the level is still partially loading and the frame rates in Fraps are just ramping up. One thing you will notice is that our test bed manages to keep the frame rates well above 100, even during the explosions. This was interesting to us considering GRAW is such a pretty looking game. Quantitatively, it appears that the explosions consistently caused a drop of 40 FPS. After running this test, we installed the ASUS PhysX P1 with the latest driver version, 2.50. There are no options within GRAW that allow you toggle on or off physics acceleration, so we had to assume the game automatically detects the PhysX card (note to developers: If we are pushing for the advancement of gaming physics, how can we not have customizable options for the game physics?). Brace yourself - here are the results of our GRAW test with the ASUS PhysX P1 PPU installed.


Obviously the first thing you will notice here is that there are again FPS drops when the grenade explosions occur. The next thing you will notice is that these FPS drops are far more drastic than in the previous test. This almost seems counter-intuitive: Why would the FPS drop more with the PhysX card, a card that is designed to offload physics calculations from the CPU, than without the PhysX card? We were kind of confused with this at first too, but then we realized what exactly the PhysX card is supposed to do.