how can I passively cool....a P4?

[Swafe]

Hi guys, after cooling a P4 chip passivly, but im not sure if its possible

Before I start, I'll add I dont know much about pentium 4's, so shoot me if I make some silly comments, but here goes..

The chip is a mobile one (Celeron 1.5Ghz) But 478 pin, so slots fine into my motherboard...its 1.3V, I'm guessing this is quite low, thus wont kick out a great deal of heat. After looking up specs, I think it dissapates (sp?) 40W of heat, so quite a bit less than them nasty 105W prescotts.

So, is it possible to run one passivly guys? And any idea how big the heatsink would need to be, or where I could get one ?


Thanks in advance

[malfunction]

A decent sized cooler would probably work just fine as long as you have some air going through the case. Personally I'd still leave a fan on the heatsink - just spinning as slow as possible (5 or 7V). I have a HTPC at home and the 80mm fans can't be heard at normal distance when they're spinning @ 800-1000rpm... A mobile celery shoudn't be putting out 40W - should be 30W max IIRC

Edit: Oh and depending on the mobo you're using it might not go as low as 1.3V (I have a mobile P4 that runs @ 1.5V default in an Intel mobo... And with a bit of pin modding it runs at 2.4GHz @ 1.5V too )... I think abit boards are best for undervolting

[alexander]

With my old Dell machine my P4 2.53ghz was passively cooled. The PC only had 2 fans, a PSU and case fan. I didn't know the temperatures but it worked fine and that was the way it came. it wasn't an exceptionally large heatsink but it did the job. I think you should just get the simplest largest one you can find.

[Swafe]

Might be 30W then, even better.

I know this might be a silly question, but a socket A heatsink wouldnt fit over a P4 socket would it?

[malfunction]

Might be 30W then, even better.

I know this might be a silly question, but a socket A heatsink wouldnt fit over a P4 socket would it?

Not a normal clip jobbie but something like a Thermalright or Zalman or such might have multiple fittings.

Edit: oh and because the mobile CPUs don't have heatspreaders you need to check if the heatsink is making proper contact. Strangely enough normal Intel OEM HSFs seem to be just fine...

[Swafe]

Ah ok, got no way of testing my chip then

How big a heatsink would do it just to test it out ?

[malfunction]

Ah ok, got no way of testing my chip then

Well I won't offer any guarantees but if the mobo is sat flat and the heatsink sits flat and still on the core (apply paste, place heatsink, remove heatsink again and check core made good contact with heatsink) then you could briefly test it will at least POST. But don't leave it that way or you're asking for trouble...

Oh and you don't need a huge sink just to run it. If the sink is too small to keep it at decent temps it might crash but only after it's heated up (though I'm not saying you could use a northbridge heatsink on it either!)

[Swafe]

Are you sure the core will be ok? As the mobiles dont have a heatspreader

[Stigggeh]

how about one of these ? Scythe

[Swafe]

Is that a bit overkill for a mobile CPU? Wouldnt that cool a normal P4?

I need something a lot smaller than that ideally

[Mr Meltdown]

You's needs to drop the volts as much as possible, then there's less W to shift

If your mobo allows undervolting to say 1.1V (some go lower still) then try that, or you'll need to pin trick it down if the mobo won't allow it.

I can run this passively using just a standard Intel HSF with the fan @ 0% (OFF) temp goes to 39 degrees C after around 2 hours, or I can run it with the fan @ 5% (next to silent) with temps of 22C:



It's the volts me says...

Cheers,

MM