So I OCed my GPU from 670MHz to 800MHz and it roughly dropped 6-7°C IDLE.

Even better is AoC, which can rack up my GPU temps rather nice to about 54°C on DX9 high.
After OC it went down to 43-44°C.

GPU fan speed is and always have been 100% and pretty much no changes to any cooling systems in my rig were done after the OC.

I'm pretty much mind****ed here, but can someone explain me this please? :/

Temps are monitored by EVGA Precision, HWMonitor and to be sure I looked with the nVidia system tools as well.
Those 3 all said thesame result.