NVidia recommends 300 watts minimum.
The GPU alone uses 75 watts.
The CPU....65 watts.
plus add your drives and fans and whatever else.
I'm a little surprised you aren't having more problems.
I would definitely replace the PSU.
I'm surprised it has lasted this long then.
I'd have serious doubts to ever buying anything from this company again, unless it is you who has already changed the original specs.
Then you should be changing the PSU when you upgraded it.