The AMD/NVIDIA drivers were the most recently installed driver on both systems. As for Intel, one was using a new Intel IGP driver I installed after I removed the 750 Ti, and the other was using whatever driver Microsoft auto-installs before I put the 750 Ti in it. If we go all the way back both rigs were originally built with GPUs and the IGP was only ever temporarily used.bruce wrote:It's probably something as simple as the order of entries in the PATH environment variable -- and likely influenced by the order of the driver installations.
PhysX is not OpenCL, but, Nvidia's latest 378.72 hotfix driver had this tidbit "- Resolved PhysX being forced to CPU when "Optimize for Compute Performance" setting is OFF."