LIGHT_5 :
Sorry I miss read. It's the cooler master i700
Okay, half-way decent budget PSU... with Teapo caps. According to a review, they tried to make up for that with better airflow and cooling in the PSU... still... It is getting near the end of its warranty period and Teapo caps aren't known for longevity, especially in heat. Unfortunately most places don't have a way to check ripple voltages... just to rule out any contributions from it.
Do you have another computer (friend's, family member's, yours) that's up to powering that 290X? you may get away with a weaker power supply (known to be good) just for testing if it works just as bad or clears up on the desktop (wouldn't risk gaming with a lower power PSU.) If it clears up, I'd look...