The Contol Panel Physx section just lets you decide which GPU to process it on, if you have more than one. You don't have a choice since you only have one (do not run it on the CPU, it's horrible). It's turned on and off within each individual games' settings though. In Metro there is a 'Advanced PhysX' option, you can turn it on and off in Metro with that setting.
post #1061 of 7826
7/23/12 at 5:09pm