-----Original Message----- Date: Thu, 15 May 2008 08:43:56 -0400 From: LAWRENCE LASKOWSKI <[log in to unmask]> Subject: CPU Fan noise I just put a new CPU in my old Dell 8400. The computer was a little = dirty inside and I blew all the dust out as best I could. =20 The computer was never this noisy, That I can remember.=20 The fan seems ok , no play in the bearings est.. Could I have hooked something up wrong and it thinks its warmer than it = is? The air seems nice and cool coming out the back. Blowing very hard at = times sounds like a jet to what it was before.=20 All I did was blow it out good remove the shroud and heat sink ect.just = replace the=20 CPU. By the way old CPU was a P 4 3.0Gz to a P 4 3.8 GHz Thanks Larry Do you want to signoff PCBUILD or just change to Digest mode - visit our web site: http://freepctech.com/pcbuild.shtml ------------------------------ I have a Dell 8400 as well and mine shipped with a Pentium 530 (3.0GHz) processor - probably the same one you had. The Thermal Design Properties of the 530 are 84W, meaning that under maximum load, the CPU will 'consume' (thoretically) 84 Watts. This is important as the cooling solution provided is for that wattage. Your new 3.8GHz processor has a TDP of 115W. Not only is it using more electricity, it will run hotter also. I suspect that the fan is woking harder to keep the new processor cool. The fan is dynamically controlled by the motherboard - it probably is an Intel 925x - (which has certain built in monitoring features disabled - read Dell proprietary) in order to adjust the fan speed according to load. As long as you reattached the heatsink correctly and used a good thermal paste, or at least the proper amount of some, you should be OK. The stock heatsink is actually pretty good (a tower heatpipe) and the fan shroud helps to funnel in air over it pretty effectively. The only concern would be the extra load on the stock power supply. (should be a 350W PS) As long as you don't have too many added in extras (HDD's, sound card, upgraded video card, etc.) you should be OK. You may just have to live with the additional fan noise. I've looked for replacement/upgrade fans but could not find anything that would support the temp monitoring feature using a 3-pin attachment (of the same fan dimensions). The stock fan has a built in diode that measures the temp of the air blowing through it and sends a signal to the mobo to increase or decrease the voltage to the fan, increasing or decreasing its rotational speed. When I upgraded my processor, I ultimately chose a Pentium 650. It has the same TDP as the 530 but with 2Mb of L2 cache insted of the 530's 1Mb. (plus an extra .4Ghz) HTH Chris Ryan [log in to unmask] The NOSPIN Group Promotions is now offering our special coffee mugs and mouse pads with the PCBUILD logo... at a great price!!! http://freepctech.com/goodies/promotions.shtml