not enough PSU for Athlon XP 3200+ ?

[mstaedt]

I just gutted my old tower PC for parts to build a CarPC. I'm using my old Athlon XP 3200+ CPU, a pair of 512 DDR RAMs, and a 60G HDD that I installed on an ASrock K7S41 mATX powered by a mini-box M2-ATX 160w automotive PS. It initially went together without a hitch and booted right up. But I then realized that I had the FSB set at 200Mhz so it only saw the CPU as 1.1 Ghz. I reset the jumpers on the mobo for 400Mhz but then it wouldn't boot. I even unplugged the HDD to try to minimize the power requirements but still no joy. I finally borrowed a 250w PSU from another desktop and it booted fine and showed 2.2Ghz.

Am I over the limits of the 160w M2-ATX trying to run this CPU at 400Mhz?

This mobo also supports 266 and 333 Mhz. Can I run the 3200+ at one of those to get some compromise between performance and power consumption?

Thanks....
Mark

[Wizzard1]

The AXP 3200+ draws as many as 75W, so you should be in the clear... Honestly, though, I'd underclock and undervolt it... You dont need performance, and that processor can run MUCH cooler when underclocked... PLus, you have to consider the high heat being in an auto can produce.

[mstaedt]

Thanks.

I'm just learning the in and outs of over/underclocking. What I picked up today is that simply setting the bios at a lower FSB will underclock. Changing the multiplier is more like fine tuning but can't easily be done anyway since my CPU is probably locked. Is this correct?

Also, I can't find anything in my mobo documentation about being able to change the voltage. Are there some mobos that don't support this? Will underclocking without undervolting still gain me some power/heat headroom?

Thanks...
Mark

[jamesjameson]

I think you are right.. your Athlon XP multiplier is locked, it was also my 2800+. I know that Athlon-MP should be unlocked (mine is) and anyway there are some mod to unlock Athlon XP multiplier if you really need.

For power consumption I think that underclocked CPU just have less power dissipation (there are less Mcycle/sec) but if you can set the voltage to the minimum to be stable at the frequency you choose I think it should also dissipate less heat!


PS: Athlon XP 3200+ are sold on ebay at high (exagerated) prices, like 80 - 100 euro. If you do not use all his power you could sell it and take a less powerfull CPU... not for money but for doing happy a guy!

Bye, have a good luck!