I just added a 120 mm fan and a PCI slot fan to my computer. It's a Gateway 700XL, with a P4, 3.06. All I had before as far as case cooling was the power supply fan. Now that I have added these new fans, it doesn't seem like I can feel air moving out of the power supply. Is it possible that I am pulling air backwards thru the power supply and maybe it will get to hot? I have two intake vents in the front of the case, air circulates front to back. These fans have lowered my cpu temp. from 40-42 idle to 33 and load of 58-60 to 48. Hard drive from 45 to 34. So I'm very happy with the temps. One last question, on the slot fan, I skipped a slot under the video card because it was almost touching the card. Is this best or should it be directly under and almost touching.