I have a medium tower system which has just been upgraded from a Duron to Athlon XP 3200. To assist cooling in general I want to add a second fan. I have options of a 4" fan at front or rear. I have placed some filter material in the front of the case to reduce dust intake - this works and gathers a lot of dust/dog hair. I was going to fit a fan as intake to the front panel mounting posiion with the idea that this would be less likely to draw dust into the DVD drive. I have had a problem in the past with another machine whre the powerful extract fandrew in dust wherever possible including the CD drive and this caused me grief. Questionis which is better - a rear mounted 4" extract fan or a fron mounted 4" intake fan? Richard