i am finalizing details for hardware for my next build and was considering the intel DH77EB board... the fan headers (cpu and case) are all 4 pin and according to the manual (pg 37 found here: http://downloadmirror.intel.com/20951/eng/dh77eb_TechProdSpec03.pdf) it looks like are all PWM controlled.

does this mean that i won't be able to use the bios to control the speed of 3-pin fans with this board? i was thinking of using the Noiseblocker M12-S1, but will it always be running at full speed with the DH77EB board?

any inputs would be appreciated!

-Scott

The motherboard fan headers supply the full 12V and a control signal to PWM fans. Only the control signal is varied by the BIOS fan controls and/or fan control software. So if you plug in a 3 pin fan it will run at full speed. As a PWM alternative to the S1 you could consider the Noiseblocker M12-PS which has a 600 to 1500 rpm range. For the money the M12-PS costs it might also be worth looking at the Noctua NF-F12 or NF-P12 PWM fans. Either of these fans could give a quieter idle than the M12-PS, typically running at around 350-400 rpm, effectively silent. Each also comes with a speed limiting cable to constrain top speeds and the associated noise.

At least the two case fan connectors can control 3 pin fans. They're adjusting nicely in my HTPC. Not sure about the CPU fan header, I suspect it can't but haven't tried.