Hello, I'm saving to build my first gaming PC and I was picking out my power supply and I started wondering, is it dangerous to have a 650w computer plugged into my wall 24/7? I know many people have power supplies bigger than this and they are fine, but I am just scared I'll come home to a house that has burned to the ground...
So is this okay? Having a 650w power supply plugged into the wall and having my computer run 24/7?
Having a 650W PSU does not necessarily your PC will consume 650W all the time. That's the maximum rating the PSU is designed for, which means your PSU can't supply more than 650W. Depending on your PC's configuration, if you use a single GPU without CPU overclocking, you will end up using less than 500W at peak. If you leave your PC powered on 24/7, which is not recommended, less because of fire hazard that we all in modern day developed countries live with unassumingly no matter what we do, but because of your electricity bill, average power output from the PSU is far less than that. Basically you are concerned about sky falling (with somewhat exaggeration, because sky falling won't happen, but fire from 24/7 powered-on computer is surely possible, if not probable.)
As mentioned above, the wattage rating is simply what the PSU can provide, not what it will actually use. Besides, even if it was running full out, 650W is only 5.4 amps on a 120V outlet. Any UL outlet is good for at least 15A.
To help alleviate any concern of coming home to a burnt down home, the use of a high quality PSU can go a long way toward peace of mind - I run all my PC's (not my laptop) 24/7 but use SeaSonic PSUs almost exclusively (a SuperFlower or Fortran every once in a while for variety). I've found this to be an invaluable source for PSU reviews to ensure you are getting the quality of power you (rightfully should) expect http://www.realhardtechx.com/index_archivos/Page541.htm