Hi, i was wondering if it is normal for a powersupply to vibrate highs and lows, when i touch the back of my powersupply, i can feel the frequency/vibration going high to low to high...., i was wondering if i need more juice, i have a geforce4, 2 cdroms and 2 hardrives connected to it. My computer runs fine tho???? Should the powersuplly be at a constant frequency??? maybe I need a bigger powersupply??? I have 400 watt supply right now....Any help would be appreciated!!!!!