Sat 19Mar2005 - I had some cooling problems initially with my Temjin TJ06 case and the Intel D925XECV2 MOBO with the LGA775 P4-560J.
The problem was the MOBO rear zone temperature (Zone B or Zone 2, depending upon whether you are displaying it with the Intel Desktop Utilities or the IDCC). The stock TJ06 120mm fans are quiet, but when the MOBO/Processor starts to heat up, their top speed of ~1200 RPM just doesn't cut it.
It took me some time searching before I finally stumbled upon an Intel document "4-Wire Pulse Width Modulation (PWM) Controlled Fans": http://www.formfactors.org/developer/specs/REV1_2_Public.pdf
, that actually described in detail their 4-Wire PWM fan specifications.
This document should be required reading for all SPCR fan buffs.
Once I knew what type of fan could be controlled by the auxilliary rear fan socket on the MOBO I was able to locate one supplier of PWM fans, JMC Products: http://www.jmcproducts.com
. I replaced the rear fan with a $20 JMC 1225-12HBHAPW 25 x 120mm PWM fan which has a top speed of ~2700 RPM. At its normal running speed for nominal system loading (~1100 RPM), it has the same airflow and noise characteristics as the stock TJ06 fan. When things start to heat up though, it ramps up and is very effective in removing the heat and hot air generated by the CPU and its cooling fan - heat which just happens to get dumped into the rear temperature zone of the MOBO.
I set the MOBO fan control parameters for this fan to ramp from minimum to maximum speed from 38° to 58° C. I am still using the stock Intel CPU cooler, have not had any problem with CPU cooling since, and now the rear zone MOBO temperature never goes out of spec. It is noisier when it ramps up, but a little noise is much better than crispy critters inside the box. I'm very pleased with the results of using this fan.
When time permits, I plan on replacing the front TJ06 120mm fan with one of these JMC fans as well. The only shortcoming to the new fans is that they are shipped with short (about 5") leads which are unusable, and one must splice them to be longer. It is nice if you have the correct MOLEX pins (08 50 0114), so that only one splice is required to extend the fan leads and then new pins are put on the end for insertion into the fan plug. If one does a lot of PC modifications, it makes sense to order a bag of 100 of these pins.
Mon 21Mar2005 - Edited this post for the benefit of other SPCR forum threads. Comments on JMC PWM Fans vs. the Silverstone ones: the Silverstone fans are good, no doubt, but they are not PWM fans, which is required for the aux rear fan on the D925XECV2 MOBO.
I opted for AUTOMATIC control, which the Silverstone SST-FP52-B Thermal Controller does (for the front TJ06 80mm fan and for a little ducted mini fan I put in my case to blow some air onto my low-end video board heat sink). Auto fan control is great, both by the Intel MOBO and the Silverstone FP52 - set it and forget it!
All 3 JMC 120mm PWM fans I ordered were wired correctly to the pins before I spliced it to make the leads long enough.
Skyline Graphics is the supplier for JMC fans: "Charles Boyd" <firstname.lastname@example.org>
Any other comments on PWM fans and cooling would be most appreciated. . .