GPU usage jumping around in game

[pooeyman]

so initially my games run great no fps drops then my gpu usage drops like a stone and lag starts
my windows if freshly installed and my specs are
RX 480 8gb XFX OC edition
i5 3330
WD green 500gb 5400RPM
seasonic 600 watt 80 plus
8gb ddr3 ram
my mobo is h61m -e asus
is it my HDD? help required

 

[Dunlop0078]

CPU and GPU temps while you're gaming? My first guess would be the CPU is throttling because its's getting too hot.

 

[pooeyman]

CPU and GPU temps while you're gaming? My first guess would be the CPU is throttling because its's getting too hot.

no the temps are fine cpu usage at 60 70 percent both temps remain below 70