http://www.jetway.com.tw/jw/motherboard ... M26GT3-SVP
Older board, no longer sold on Newegg.com, but it has some of the nicest features for a silent PC. Main features that benefit underclocking and undervolting are: manual selection of CPU multiplier and voltage. Multiplier as low as 5x. Voltage down to 1.0 volt. Unfortunately, one cannot undervolt the CPU via this method and still have CnQ. Luckily, Jetway has this feature called CPU vcore 13 shift, which basically takes the selected VID and then overvolts/undervolts by a given percentage, selected by you in the bios. That way, you can underclock the CPU to 5x multi, keep the vcore at default, and then use the vcore shift feature to reduce vcore. This allows you to successfully use cool and quiet or RMclock once in windows to further reduce multiplier to 4x and vcore to .800 volt. One thing to keep in mind though, set the vcore shift feature to no less than the max needed to achieve full desired clock speed of CPU once in windows (say 1.1 volt it running at 2.0GHz) because programs like RMclock cannot overvolt the CPU, but only run it at it's highest default vcore. For example, setting the CPU voltage to the max in RMclock, which is usually the default voltage for the CPU, will only run the CPU at the voltage set in the BIOS using the vcore shift! Since RMclock does not know the bios is changing the vcore, it thinks the vcore is at default, so your vcore shift is now running the true vcore at 1.1 volt. In this scenerio you must set the undervolted vcore to 1.0 volt to achieve the 0.800 vcore desired for 800MHz operation, and yes, you can even go just a little bit under 0.800 vcore using this vcore shift feature. I'm usually running at 0.780 true vcore. Since RMclock can't read the true vcore, Speedfan is needed, and always reports the corrected vcore. CPU-z is hit and miss, usually reported the correct vcore only if speedfan is running at the same time, for some reason.
The jetway m26GT3-svp also offers PWM fan control to slow down the stock CPU fan to ~2000 rpm. The only real drawbacks are lack of AM2+ support and the inability to perform S3 standby.
CPU: Sempron LE-1100 @ 211 FSB (850MHz/0.780, 2.00GHz/1.1)
mobo: Jetway m26GT3-SVP
RAM: 2 x 512MB DDR667
Video: ATI x300se 64MB Dell branded card
HDD: 200GB Seagate 7 series with SATA adapter
PCI cards: Hauppauge PVR-250
Optical drive: Lite-On 16x DVDRW
PSU: Rosewill 200 watt SFX
Case: HP Pavilion (former HP 6835)
OS: MCE 2005
Power consumption, typical Load: 65 watts
Before this computer was repurposed as my HTPC, it was an internet browser, using the IGP and no capture card, idle power consumption was 37 watts, and load 55 watts cpu only, up to 62 watts with IGP+cpu load during certain games.