Author: Brian Lee Page: 4

The first thing I noticed when I turned on the server is that this guy is loud!  I was fairly surprised since all the Dell office machines I've used were dead silent.  But not this server, it was freaking loud.  The server has two fans in the back, one inside the power supply and the other is an exhaust fan connected to a shroud that covers the CPU.  The CPU has a heatsink but doesn't have a fan on it.  Instead, the shroud directs the airflow from the heatsink and out the case via the exhaust fan. 

This is very typical for Dell.  Many, if not all of their computers use ducting to cool the CPU instead of a fan mounted directly on the heatsink.  I guess this keeps things quieter.  Upon closer inspection, I found that the power supply fan was very silent.  The culprit was the exhaust fan.  This fan moves a large amount of air and this is where all the noise comes from.  I decided to replace this fan with a quieter fan.  I chose to use a new Nidec temperature controlled fan that I had laying around.  This fan moves a decent amount of air and changes speed in accordance to the ambient temperature.  Time to take this sucker apart.  Off comes the shroud, then the exhaust fan. 

You can see that the exhaust fan is quite a bit thicker than a typical 92 mm fan. 

Unfortunatly, the exhaust fan uses a connector to the motherboard that I haven’t seen too often.

I thought about cutting off the connector and soldering it onto my new quieter fan but since I didn't know the exact specs of the connector, I decided to just splice a regular old molex connector to the Nidec and forgo the RPM monitoring.

I put the Nidec fan into the case, replaced the shroud and booted the server back up.  The fan powered up fine and all seemed to be going well until I got a message from the system that the system fan was missing.  Crap.  It seems like the BIOS checks to make sure the exhaust fan is connected and running before booting from the HD.  You can ignore this message and proceed by pressing F2, but this meant that every time I rebooted the computer, I would have to press F2.  That's not cool.  I searched in the BIOS and looked for some setting to allow the system to continue to boot even if the fan was not detected, but such a setting does not exist.  Oh well.  How did the new fan perform?  Good question.  I was afraid that since the Nidec moved less air, there wouldn't be enough cooling for the CPU.  In order to test this, I closed up the server and ran Prime95 for 48 hours.  Prime95 posed no problem at all.  Just to make sure the CPU wasn't cooking, I opened the server case immediately after Prime95 was running for several hours and felt the heatsink on the CPU.  Cool as a cucumber.  Great, the new Nidec works well as a exhaust fan and is much much easier on the ears compared to the original fan.
 

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