IS Saga II 500w much for my pc? I got error and thinking in less power supply.

[presidentAkos]

Hello guys, I would know that 500w is much for pc or not, because I got the next problem since long ago and unknown smart people said that my power supply is can be reason:

In BIOS, where voltage should be 12V its always about 15-16V with red text..
I checked temperatures with FanSpeed and everything is ok, only cpu's icon is "fire" sometimes about 60C but its not high I think.
My pc:
Amd Phenom 9550 x4 2.20 ghz
GTS 250 1GB 256 bit
4GB RAM, 3,50GB usable (1x2GB, 2x1GB)
Random 250GB HDD

+oh, when I was on windows 10 I had fps drops in every game, for example cs 1.6, cs:go, league of legends, long ago I never had lags in these game with that config, since I installed windows 7 I had no lag in cs 1.6 (didnt test cs:go and lol), question is WHY?

 

[bignastyid]

Your PSU is overvolting which is bad and can damage other components. You should replace the PSU asap.

 

[presidentAkos]

Your PSU is overvolting which is bad and can damage other components. You should replace the PSU asap.

I think nothing is damaged but that problem is exist since ~1 year. I can ignore or use 15-16V, whats will happen if I ignore?
And if I replace does I need 500w or 400w is enough? (my pc case has +4 12cm fans too)

 

[bignastyid]

Nothing maybe damaged yet, but if you continue to ignore it that's whats likely to happen. 400w isnt enough 450w is the minimum recommended for the gts 250.