Did you reinstall drivers?

280x to 390...not much of an upgrade in the first place

i reinstalled drivers 2 times normally, 5times using ddu. I later noticed that as i decrease the settings (goes for csgo, war thunder and aftereffects) (syntetic benchmarks work fine) the gpu usage drops. so do the fps. cpu usage is on about 50% spread among cores in games. So i assume it isn't a bottleneck on the cpu (if it ran fine on 280x it shouldn't be worse, it it was a botleneck it would be the same if anything).
I upgraded cuz the 280x died after a year and a half.

The 390 is not faulty. It works fine on my brother's rig (100% usage with ocasional dips) which is normal for games. i get constant 100% 0% fluctuation.

1 more thing, i am not runing any frame targets of v sync. I have however enabled freesync (modified the range from 35Hz-90Hz to 57Hz-144Hz) because of the low fps to make things more bearable.

ehhh is it even worth it going from a 280x to a 390?

I said earlier that the r9 280x died, that's why i went to the 390. I didn't expect to have so many problems tho -.-

390 supports freesync  (280x does not)

i like the 8Gb of ram for 3D rendering and it helps on the monitor i have