Can a weak power supply cause PC performance issues?

[Bionic_Tuna]

I have a 400 watt power supply. I got a Saitek Eclipse and the backlight was apparently too much for it to handle. After removing my very modest overclock I got my pc to boot once again. This leads me to believe that my power supply is just barely enough for my PC. I've had some FPS issues in games that I shouldn't and had tried everything. I was wondering if a lack of extra juice from the PSU could cause this?

 

[Sieravor]

Poor quality PSU's can cause an enormous amount of trouble. Clean, stable, and plentiful power is something every computer needs and wants in order to run properly. So, yes, your PSU is capable of causing a problem of this nature. OCZ, PC power and cooling, and some others are great PSU's. Check the thread, you'll see a multitude of great suggestions for PSU's.

Also, keep in mind that alot of the ratings you see for PSU's aren't entirely accurate. Alot of the time you'll get less than what your PSU is rated for, with exception to a few select brands.