I installed a Nvidia GT640 DDR5 with a Radeon HD 7870 Tahiti LE today to try out hybrid Physx with Hawken. First, I confirmed that I configured hybrid Physx correctly using Hybridiz by comparing FluidMark 1.50 benchmark runs at 1280x720 with Physx GPU enabled and disabled. The results were 70 fps using the GT640 and 22 fps with a 3 GHz Intel Q9300 CPU. I moved PhysXDevice.dll out of C:\Program Files (x86)\MeteorEntertainment\Hawken\InstalledHawkenFiles\Binaries\Win32 and configured the Physx setting to High. Frame rates averaged about 30 fps in the drone firefight in the tutorial (eyeballed 'stat fps'). With Physx set to On (CPU based Physx) and the game restarted, fps seemed higher, closer to 40 fps. I expected Physx On would be lower than Physx High, not higher.