I have been told all external surfaces of componants in a computer shouldn't exceed 25 degrees celsius to be the absolute safest. Granted this can be hard to get without spending a little money on some good fans. If you want the absolute best fan that I have read reviews on try the Thermaltake Global Orb. More info at www.heatsink-guide.com

------------------
I am a bomb technician, if you see me running try and keep up