Would like to know how does one determine if the power supply is large enough. I am running an Athlon 1.33 gig on a ABIT KT7A-RAID, 512 mb PC-133 ram, two 30 gig HD in RAID 0 and an additional 8 gig HD. I also have the usual array of a sound card, video card, an ethernet card, a USB hub, a CDRW and a floppy drive. I have one case fan and just ordered a SK-6 heat sink with a Delta fan. I am planning to add another case fan, a firewire card, and maybe a DVD drive. At this point I don't have a problem, but with all these additions, I am concerned that my current 300 W power supply will not be enough. Any insight from the experienced ones will be much appreciated.