I was playing Dota 2 when my FPS suddently started dropping, then i made some tests and i found out this:
My GPU usage is spiking, i dont know why...
I alreadly tried to reinstall the drivers and format my PC and i still doesnt know why its like that...
XFX R9 280X 3GB Black Edition
FX 9590 Vishera
8GB HyperX Blue
OCZ 700w stealthxstream
4x Arctic F12 Coolers
That's expected behaviour as you are running a power virus application, try testing 3DMark instead to monitor GPU usage.
As for the FPS drops in Dota 2, are your Motherboard VRMS overheating?
You can monitor the CPU Package temperature with HWINFO64. If you're below 64c, you should be okay.