why did cooling advantage vanish?

[no1uno]

I had (as of yesterday afternoon) a 1GHz TBird @1.2GHz (12x100), with the heatsink/fan that came with it from AMD, a copper shim, and some RadioShack thermal grease. It was was running at 30 degrees C idle and 48 degrees C stressed.

No complaints.

So I bought a Volcano II and installed it with the shim and Arctic Silver II -- figured I was on the fast track now! And sure enough, right after booting it cooled down (monitoring with MotherboardMonitor5) ... gradually ... to 24 degrees C! And maximum stressing would take it no higher than 41 degrees C! Wow, what an improvement!

So, paid some attention to other things in life for a while, came back to the PC and noticed it was idling at ... 30 degrees C. So I stressed it and it got up to ... 48 degrees C!

This seems bizarre to me. The Volcano's heatsink and fan are both much more substantial than what came with it, and the Arctic Silver II certainly looks oh so much cooler (as it were) than the RadioShack goop. So, why the temporary wonderful results followed by the same ol' same ol'?

Any ideas anyone?

Thanks!

(For anyone who thinks it might matter, the mobo is an Abit KT7, memory is a single Crucial 128MB PC133 CL2 DIMM, all in a 3DCool Tornado case with 4 fans. The new CPU fan varies between 4687rpm when nothing’s happening to 4821rpm when things are toasty.)

[Metaxas]

Well, I don't know what that HSF looks like, but there might be gunk in it, espically if you live in a house with smokers. Clean that and the fan real well, and you might want to check to see if the HSF is still mated with the slug good too. Also, try cleaning your case fans, that can make a big difference too. Gunk and dust on heatsinks = bad.

[no1uno]

Well, golly, I can answer that!

The PC is only a few weeks old (see FYA http://www.lukefisher.com/building/...), and there are no smokers and an excellent electrostatic air filter on the HVAC system, which I cleaned out (coincidentally) 2 weeks ago.

Here's the Volcano 2 after I cleaned off all of the gunk associated with the foam thingy:
http://www.lukefisher.com/overclocking/oc-05.jpg

And the really-clean 1GHz (pencil-tricked) Athlon, waiting with the really-clean shim for some grease:
http://www.lukefisher.com/overclocking/oc-07.jpg

And the same, with lots of that lovely viscous Arctic Silver II heaped on top:
http://www.lukefisher.com/overclocking/oc-08.jpg

And the Volcano II afixed:
http://www.lukefisher.com/overclocking/oc-10.jpg

And the whole inside:
http://www.lukefisher.com/overclocking/oc-12.jpg
(got a couple of those rounded IDE cables with teh AS2 & V2...)

Any other ideas?

[Metaxas]

I hate to rain on your parade:

First problem...you used WAY TOOOOO FREAKING MUCH artic silver...man DAYUM.....whewwwww...the coating should be no thicker then about 0.003" to around 0.008" thick..You should try reading the instructions, you might have better luck.

Second problem...pencil lead (i'm assuming you used a good ole no 2 graphite pencil?) is a RESISTOR...when are people going to learn that? I don't know why it works sometimes, but still, bad. You should use a rear window defroster repair kit type thing, which you can get an any local auto store.

;D