Hi John, Truthfully, I haven't used a rear fan as yet. I purchased the modded side panel w/fan/LED & turned the fan to blow in- happens to blow directly on my memory & cpu. All this amounts to is, in my case, the warm air being taken out via the power supply vents & it's own fan. My internal case/cpu temps stay at around 37-40C degrees . I'm running 120 GB & 60 GB hard drives, DVD-ROM, CD-RW, floppy, Soundblaster card, & ATI Radeon AIW 128mb graphics card (gaming & video authoring) & never see the case get overly warm. The only thing I'd like to see, though this case's price is so low for what you get, is front mic/headset. I would say to get/borrow a rotozip or dremel to cut away the backing where you intend to pu t the fan- ought to take about 2 minutes at most w/a steel bit? Lynn PS- I just ran across this one at Dealsonic.com (though I have no personal experience with the brand)? Codegen 4046. It has front (2) USB & mic/headset: http://www.dealsonic.com/caseonly.html Many other inexpensive cases. PCBUILD maintains hundreds of useful files for download visit our download web page at: http://freepctech.com/downloads.shtml