As computer parts get faster and faster they tend to generate more heat, the current case configurations today usually have one exhaust fan locate at the top of the case, and for the most part this works, but it doesn't cool the things at the bottom of your case very efficiently. So many companies have come out with solutions to help this problem in the form of PCI slot coolers that suck the hot air from the bottom of your case and expel it out the back.
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*Review: DragonsteelMods (
http://dragonsteelmods.com/index.php...&Ite mid=38)*
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