Re: overclocking GPU
I used to run my eVGA 8800GTS KO ACS3 640MB @ 650/950 with the fan @ 100% and my temps were around 56' to 58' C idle and upper 60's, maybe low 70's, under load. Your temps are fine.
AMD FX-8320 Vishera 8-Core 3.5GHz (4.0GHz Turbo)
G.SKILL Ripjaws X Series 16GB (4x4GB)
EVGA SuperClocked GeForce GTX 760 2GB w/ EVGA ACX Cooler
MSI GTX 460 (Dedicated PhysX)