I was looking to upgrade the CPU heatsink in my computer with the Thermaltake Intel 775 Fan and was wondering if it would mount on the motherboard? Here is the link so you know what it looks like http://www.amazon.com/Thermaltake-CL-P0497-Intel-775-Cpu/dp/B001CCGYU0/ref=cm_cd_al_qh_dp_i
Actually, the heatsink from a Dell GX280 tower will fit. It is a nice copper tube with steel fins and almost twice as tall. It is too tall for the green plastic shroud though. On another note, the rear fan in all of the 4700s that I have worked on(9), was blowing IN ! I have worked on hundreds of Dells and I have never seen that in another model. I turned the fans around to exhaust and they ran much cooler.
I have a Dell 4700 with Win XP. Yes it is old but still works. I installed a case fan in the side panel ( 92mm ) blowing in, and it increases the cooling considerable. Using rubber washers for noise insulation helps so the low noise is not distracting. The modification is cheap and effective. It cools the inside including the hard drives.
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What is a good CPU and motherboard upgrade for the Dell 4700. I know I need a faster computer but cannot afford one now. I can afford a CPU, motherboard and power supply
Any micro-ATX motherboard should fit, but if you upgrade to something more modern, you'll likely need new memory, too (4gb of DDR3 is only around $25, though), and a 92mm chassis fan (around $10).
I have first-hand experience in this area, having upgraded a Dimension 3000 (which shares the same chassis) to an ASRock AM3 motherboard with quad-core CPU.
Note that the new Socket 1150 platform doesn't support XP, but AMD still does.