Dimension 8400 fan goes nuts

I've also been having very loud fan problems with my Dell Dimension 8400 I bought a few months ago.

PC Specs: P4 3.4 800 fsb (model 550, LGA 775 Prescott), 3 GBs of RAM, ATI x800 XT 256 mb, 2x74GBs HD 10,000 RPM RAID 0, etc...

Except for the extremely loud fan (Delta AFC0912DE), the system's performance is amazing and I'm very happy with that. I've looked everywhere on the net and I realized there is a lot of other people facing the same problem. So I think I tried all the suggestions to fix the loud fan problem.

One of the first things I thought was changing the Delta fan for a quieter one because after all, Deltas are very famous for 2 things: their extremely high air flow and off course their noise! Trust me there are loads of both… However the Dell mother-board has this unique 4 pin connector which is not compatible with any decent silent fan.

Some people managed to solve the problem by updating the bios with the new A03 version (available from dell online support website) and also by changing a few power management settings on it. You can check out some posts on this solution of this forum:

Unfortunately, none of those solutions worked for me. So then tried the limiting resistor solution proposed by someone in a forum. I tried several different values (from 1 Ohm to 100 Ohm) connected to the red wire of the 4 pin Delta fan. For instance, with a 56 Ohm the fan would not spin at all and anything lower than 11 ohms would make a lot of noise, so I after a few test I went for a 22 Ohm.

The system became nice and quiet however I started noticing it was running really hot (touching the heat-sink could fry my hand!). I could tell the cooling system wasn’t doing its job properly. Concerned with stability issues and the overall lifespan of the system, I've realized that the limiting resistor was not the answer so I decided to go the whole nine yards and replace the whole cooling system.

So I started looking for quiet cooling solutions for the LG 775. I didn’t want to go for water cooling since a proper kit that would actually be silent would cost at least £150. After a few days researching, several reviews, forums, etc, I’ve decided to go for the huge Zalman CNPS7700-Cu heat-sink. This heat-sink had excellent reviews and besides it's huge size, heavy weight (almost 1 Kg of copper), and motherboard compatibility issues, it's the best heat-sink to cool the hot Pentium 4 socket T processors (LGA 775 Prescott) silently!

However I haven’t heard of anyone attempting to fit this monster into a Dimension 8400... It sounded like a crazy thing to do and I knew there would be no easy plug and play here but it had to be done. I measured my mother board and the interior of the case and everything seemed to be compatible. The dimension 8400 could take the huge Zalman 7700 Cu. So I ordered one which came up to £39.01 including next day shipping from www.tekheads.co.uk.

Once again there were some nasty surprises whilst installing the beast. Since Dell always try to do things a bit different, as soon as I removed my original Dell heat-sink, I realized that none of the fixing sockets that came with Zalman would fit the mother-board. Basically, Dell has drilled wholes in different places than the rest of the world!

It all seemed to be the end but I wouldn’t just give it up so easy... I have watched enough Macgyver to know that there's always a way ;)

Below is link to a little guide with photos, etc of how I got the Zalman CNPS7700-CU to work with Dimension 8400 and also the achieved results, etc.

I hope this is is useful.