I'm running 64 bit Windows 8.. decent specs.. SSD/16GB of ram/AMD 6 Core 1055T and an AMD 7950 3GB video card. I tried playing Crysis 3.. noticed it did not matter what settings I used.. even at the lowest settings my frame rate would be quite low.. switched to an older video card.. same thing..What was strange though is if I opened up Resource Monitor or an utility which monitored the GPU they were not being pushed at all.. CPU was 50%.. GPU was 20%..
Hyper V was installed.. and there was 6 VM's in a saved state.. but they were not being started when Windows started. I removed Hyper-V and now everything is normal, and well Crysis 3 is a thing of beauty..
But I'm not sure why Hyper-V would stop other apps from getting the full use of my hardware?