well first off it's often a good idea to make sure your bios is up-to-date. plus always overclock in the bios. you arent software overclocking the cpu?
good programs for overclocking the gpu and monitoring temps are msi afterburner or rivatuner.
go to the download section here and you will find some usefull programs. namely cpu-z. gpu-z. occt. linpack. prime95...



