Cpu downclocked and downvolted when the gpu is put under load.

[benmaister]

Cpu downclocked and downvolted when gpu is put underload. I have an Asus fx550ui. The cpu runs fine under stress tests on its own at 3.4ghz. When I stress test the gpu the cpu immediately drops to 1.3ghz. It is a huge problem when I play league of legends as it causes pretty severe stuttering. I have replaced the thermal paste on the cup and gpu to make sure it is not simply thermal throttling. The downvolting is from around 1.1v down to .8v at the same time as the cpu downclocked.

 

[shmoochie]

1. Make sure you bios and cpu/gpu drivers are up to date.
2. I know you said you replaced the thermal paste, but did you also check the temps using hwinfo or something similar? You might also make sure that the thermal pads on the heatsink are actually touching the VRMs and VRAM. Sometimes those heat up and downclock the cpu.
3. If temps are fine, and only if they are fine, you could disable "pwm processor hot" in the bios. It could be a faulty sensor.
4. Have you by chance recently purchased a new charger? If you get the wrong one, it can do funky stuff.