I have this unsual observation in my X-Qpack case with Antec TruePower 380S PSU. The rear 120mm Neon exhaust fan when connected to the Fan-Only connector of PSU runs slower and seems to respond to SpeedFan controls when I slow down the CPU fan!.

My board is ASUS P5V800MX (uATX) with 805D on stock cooler. The PSU fan monitor connector is connected to "Chassis Fan" header on the mobo. Yes, Speedfan can monitor and control the chassis fan. But I am tweaking the CPU fan speed , then the 120mm will slow down as well. Its connected to Fan-Out lead. What gives ?.
At 30% Fan1 the CPU speed is 3200rpm and PSUfan is 1450 rpm. No idea what the 120mm Neon fan is running but it appears either 1000 rpm or a little slower. At that rate it is practically inaudible. At 40% the whine is annoying. At 25% sometimes, SpeedFan reports that CPU is 0 rpm but I can see its still spinning. Maybe the lower range speed cannot be read correctly!. Still I dont like 45DegC idle temp when ambient is around 32 DegC. Burns kicks it to 55DegC!. And the 120mm speeds up like a bad-out-of-hell in lair!. Noisy sucker!.

You kinda lost me...but it sounds like you just need to put the fan on another Molex, and have you tried to use the AMD Cool and Quiet option for controlling fan speeds/temps?

Quote: Originally Posted by $SOLID$ Necro You kinda lost me...but it sounds like you just need to put the fan on another Molex, and have you tried to use the AMD Cool and Quiet option for controlling fan speeds/temps?

The Fan-Only molex for Antec PSU seems linked internally to the PSU heat-sensor. It allows the fan to spin more slowly depending on the load on the PC. The standard molex supplies standard 12v to the fan and it was way too noisy for me. Without a fan controller, I use SpeedFan V4.28 to control the CPUfan. I just find it strange that this somehow links to the 120MM fan speed when I connected it to the Fan-Only Molex of the Antec. Sound difference is significant and idle/load temps are reasonable for a Pentium D dual-core (2.66Mhz OCed to 2.85). I wanted more consistent silence from the case as my iTunes played with full-screen visualization loads one CPU to 100% while the other CPU just barely clocks 5% occasionally.

For the Intel chip, enabling power-saving mode is very similar to AMD Cool and Quiet. My main machine is Opteron 165 in the Aria case and this P4 is my daughter's machine with TV tuner and PVR.