Underclocking

[Superkev6969]

Hello
Anyone any experience of underclocking.
I would like to change my Intel2.8/MSI 845PE into a fanless, noiseless PC for my bedroom to run my CCTV system and occasionally surf the net so speed is not important.
My MSI mothrbaord only seems to allow overclocking the fsb being locked at 133mhz but not sure if this is general with all P4 boards?
I wonder how much I would have to slow down the CPU so my Zalman heatsink fan could be dispensed with?
Thanks
Kev

[Rave]

I'm not sure why the MSI won't let you run at 100MHz FSB- is there a jumper you need to move maybe? Anyway, if you underclock to 100 you should be able to drop the CPU voltage drastically, probably down to 1.3-1.4V; along with the reduction in clockspeed that should drastically cut the processor's heat output, and you may well find that running passive is possible if your case airflow is up to the job.

Intel processors aren't as good as AMD for underclocking as they're multiplier locked, so you can't recuce the multi (except on Xeons, I know). I once ran a Duron 1400 at 1600MHz (which I know is actually an overclock) on 1.4V, and it ran cool as a cucumber.

Rich :¬)

[Shogun]

I swop you a p4 rig that you will be able to run passively easily
Intel have a thing called thermal throttling which slows down the chip when it gets too hot. I have seen a demo of someone taking their heatsink off with the pc still running. Not sure if it stayed in windows though. Might be easier than underclocking.