Hello everyone! just recently upgraded my PSU from 450 to 550 watts coz ive got a lot of stuff connected to my desktop. My motherboard is ASUS P4C800E DELUXE, 4x1.0gb RAM, 3x80 gb HDD, with ASUS tv fm card & GEFORCE 7300GT (512 MB), and 2 x combo DVD rom, including AUDIGY 4 sound card for my 7.1 creative speakers on the graphics & PCI slots respectively. with all the 8 USB 2.0 fully loaded with USB hub, web cam , HP printer, and blue tooth devices adding to that my internet modem simultaneously working....id say am satisfied with the performance for the multi tasking. I"ve added two fan casing aside from the PSU fan and CPU fan and graphics card fan to take care of the cooling system. prior to this upgrade, i have encountered booting problem with either one of my HDD missing randomly or even the master drive itself and crashing event in blue screen. I suspected that the power supply connections might be only loose but the problem keeps on coming back. and finally ive fixed it. So, if you plan to have your computer fully loaded and satisfying id recommend you to provide ample power supply to avoid crashing, hung ups and irregularities. do hope this helps a bit to those who needs it...ciao!