Can a poor PSU cause performance issue?

[bonoz]

I have a generic 450W PSU running a Phenom II x2 (unlocked to x4), 4GB RAM, ATI HD5770, 2xOptical drives, 6 case fans, Creative Sound Blaster, etc.

Whenever I run a "heavy" program/utility I can feel the change in sound from my PC. Sometimes, the PC will not boot after I run those "heavy" programs. I then have to unplug it and plug it back in to "reset" the PSU.

Would using a 450W PSU from a known band = better performance and everything?

 

[Slaymate]

Probably yes. It sounds like your old power supply is working as hard as it can to barely supply the required minimum. And if it's working so hard that it has to be "reset" (for lack of a better word), then it's probably on the verge of dying (which can damage other components sometimes).