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.
CPU PhysX != GPU PhysX. GPU PhysX will probably be doing more. The card you are running PhysX on is slow. The benchmark you did may not represent a games performance delta, because the game may not be doing the same things in both instances, whereas the benchmark is.
Interesting. However, I saw people claiming that Hawken can't run Hybrids since the game is reverting all files back to its normal state. There is an easy way to check if PhysX effects are GPU accelerated - set PhysX to High and look on any of Turbulence effects (energy generators, for example) - are the particles behaving all swirly or fluid-like, or are frozen in place or flying in one direction ? As for CPU PhysX, with PhysX Particles "On" (that means only particles debris effects) it holds pretty well, above 30 fps, according to my benchmarks.
Thank you. The answer was in front of my face and I could not see it because of my preconception that Physx options are to use a CPU or to use a GPU. Now I understand that hybrid Physx is working successfully, as much as it can, on my system, and I did not recognize that, In other words, PhysXLevel=1 means some Physx effects are active and will be generated by a Nvidia GPU if available, otherwise the CPU will crunch the numbers. PhysXLevel=2 means that all available Physx effects are active and will be generated by a Nvidia GPU if available, otherwise the CPU will crunch the numbers. Performance by CPU will be horrible. I have only played the tutorial so far, so I have not seen generators yet.
After using GPU-Z to watch a load of zero on the GT640 and Windows Task Manager to watch CPU usage head toward 100% in a furball, I conclude that the GT640 is not running any of the Hawken PhysX on my system that has the AMD 7870 XT + Nvidia GT640. I used Hybridiz to enable Fluidmark 1.5.0 to use the GT640 but cannot do the same for Hawken so far.
