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#1
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Lapping a P4?
I have a P4 2.4B stepping SL6SH. I was shocked at how rough the heat
spreader is. I mean, it almost looks like it fell off the back of a truck, and skidded along the road for a mile or two. :-) The obvious solution is lapping. But I see that there is a small hole in the heat spreader, and I'm concerned that if I were to lap the heat spreader, debris would pack into the hole. Worse, there appears to be a very small gap between the heat spreader and the substrate (?), so the heat spreader seems to touch the CPU only at the slug. This would mean dust, silica, and metal shavings could pack in under the heat spreader. I'd really hate to ruin an expensive CPU, but on the other hand I'd like to get more than just an extra 330 MHz out of the CPU. Is lapping the slug advisable? What if debris gets under the slug, will / may it short out something? What would be good to temporarily plug the hole in the slug, maybe a very tiny dab of silicone sealant? -- Tony Sivori |
#2
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Before you do anything, try running the cpu cooler by collecting the air from your airconditioner by taping a plastic bag over the outlet, and ducting the cool air to the cpu fan using a vacume cleaner hose. Check to see if the lower temperature gives you any extra performance. My guess is that it won't. So you'll save yourself from defacing your cpu. I've been down this road with old P4 1.8A. I even removed the IHS totally from my cpu. In my case, it was a waste of time, but some people report better temperatures when the IHS is removed. Once the IHS is removed the chip looks exactly like a coppermine P3 or Celeron but smaller (if that helps) "Tony Sivori" wrote in message ... I have a P4 2.4B stepping SL6SH. I was shocked at how rough the heat spreader is. I mean, it almost looks like it fell off the back of a truck, and skidded along the road for a mile or two. :-) The obvious solution is lapping. But I see that there is a small hole in the heat spreader, and I'm concerned that if I were to lap the heat spreader, debris would pack into the hole. Worse, there appears to be a very small gap between the heat spreader and the substrate (?), so the heat spreader seems to touch the CPU only at the slug. This would mean dust, silica, and metal shavings could pack in under the heat spreader. I'd really hate to ruin an expensive CPU, but on the other hand I'd like to get more than just an extra 330 MHz out of the CPU. Is lapping the slug advisable? What if debris gets under the slug, will / may it short out something? What would be good to temporarily plug the hole in the slug, maybe a very tiny dab of silicone sealant? -- Tony Sivori |
#3
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Richard Hopkins wrote:
"Tony Sivori" wrote in message ... Worse, there appears to be a very small gap between the heat spreader and the substrate (?), so the heat spreader seems to touch the CPU only at the slug. Not quite correct. This would mean dust, silica, and metal shavings could pack in under the heat spreader. No, that won't happen. Round the edge of the IHS is a bead of elastic bonding agent used to hold the slab to the substrate. That will stop any crap getting in. I expressed myself poorly, sorry. I meant there is a gap at the bottom of that small hole in the heat spreader. The gap is too small to be seen clearly by naked eye (mine anyway) but I confirmed it by very gently probing the hole with a dental pick. So was worried about dirt from the lapping operation packing into the bottom of the hole and then into the gap at the bottom of the hole. However, the bond is actually designed to compress under the clamping load of the heatsink, theoretically allowing the IHS to press firmly against the core, optimising the thermal bonds. It's most unlikely, but if you let a large amount of solid crud build up around the edge of the IHS, the bond could be prevented from compressing, thus making the heat dissipation worse! Is lapping the slug advisable? It ain't gonna do any harm if you do it properly, let's put it that way. However, if you expect an extra 500MHz out of your CPU, you're likely to be disappointed. I'd be happy with another 50 MHz, and delighted with anything more. What if debris gets under the slug, will / may it short out something? Most unlikely. What would be good to temporarily plug the hole in the slug, maybe a very tiny dab of silicone sealant? Yeah, that'd fly. To be honest you could leave it plugged permanently if you wanted to. The hole is primarily there to allow gases liberated by the setting sealant to escape. Thus, it's job is really done by the time you get your grubby mitts on the chip. That was my next question, what is that hole for anyway. Thanks for answering it before I even asked. -- Tony Sivori |
#4
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John wrote:
Before you do anything, try running the cpu cooler by collecting the air from your airconditioner by taping a plastic bag over the outlet, and ducting the cool air to the cpu fan using a vacume cleaner hose. Check to see if the lower temperature gives you any extra performance. My guess is Not a bad idea, I'll try it. I'm using the Intel fan and heatsink so there are better ones available. -- Tony Sivori |
#5
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"pete" wrote in message .com... This is what I did to lap my 2.0. I packed a small amount of heatsink compound into the hole so that the hole was sealed flush with the compound and not allow any foriegn material to get past deep into the hole. Only enough to close the hole. I proceeded to lap the IHS then sucked the hole out, with any fine metal particles and compound. Sounds strange but it worked perfectly. Been running it fine at 2.66 with stock HSF and voltage. Underload max it hits 42c. At idle it sits at 30c. Pete My 2.4 @ 2.7 is running at 45c no load, and around 55c full load (seti@home). That is with an Abit board and some say they measure temps hotter than others. Overclocking is kind of disappointing; no better than 2745 MHz with memory at 190 MHz. I tried cutting the memory back to 1:1 so it couldn't be a factor, and the best I got was 2880 MHz - and that locked up at the log on screen. At 3.0 GHz, the boot screen stayed black, even though I had boosted the voltage 10%. At 2800, it ran but was very unstable; frequent program crashes and some blue screens. I guess I shouldn't complain, it is one hell of a lot faster than the PIII 650 @ 900 that it is replacing. -- Tony Sivori |
#6
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Optonline wrote:
Are you asking if you should lap the heat spreader? Yes. No, no, no, you want to remove it. Its a standard flip-chip underneath. I wished Intel would have just left it alone and not glued that damn hunk of metal on it. Here, read this: http://www.overclockers.com/tips1087/ Thanks for the link. I had stopped reading overclockers.com quite some time back; they had gotten so AMD-centric, and their insistence of referring to the P4 as "PIV" for some reason annoyed me considerably. The photos, especially on page 3 were very revealing. It looks like junk packing into the vent hole of the heat spreader during lapping is a factor, although not likely to cause damage. As for removing the heat spreader, between the hazards of the operation and the increased chance of damage to the core later (when mounting and unmounting the heatsink) I think I will pass on that for now. I cannot easily afford to buy a new CPU if things were to go badly wrong. -- Tony Sivori |
#7
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Thanks for the link. I had stopped reading overclockers.com quite some time back; they had gotten so AMD-centric, and their insistence of referring to the P4 as "PIV" for some reason annoyed me considerably. The photos, especially on page 3 were very revealing. It looks like junk packing into the vent hole of the heat spreader during lapping is a factor, although not likely to cause damage. As for removing the heat spreader, between the hazards of the operation and the increased chance of damage to the core later (when mounting and unmounting the heatsink) I think I will pass on that for now. I cannot easily afford to buy a new CPU if things were to go badly wrong. -- Tony Sivori I found that the surface where the HS faces the CPU is very curved, looking at it with a magnifing glass i could see where it looks like the outside edges of the cpu have been cut with a lazer leaving some raised edges. I lapped mine to the point where the letters were almost gone and the surface was still not flat. I'm sure you could get it flat but you would remove all the lettering. I think the thin shim on the cpu is soft enought to conform better to the heatsink because it it soft. I removed the shim and used some ARTIC silver and it lowered the temps a few degrees over the Intel pad. DOUG |
#8
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Thanks for the link. I had stopped reading overclockers.com quite some time back; they had gotten so AMD-centric, and their insistence of referring to the P4 as "PIV" for some reason annoyed me considerably. Yes and the fact that they won't except the fact that the new 800 FSB cpu's have knocked them off the top..... DOUG |
#9
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"pete" wrote in message .com... I proceeded to lap the IHS then sucked the hole out, with any fine metal particles and compound. Sounds strange but it worked perfectly. ?? Bet it tasted funny... ;-) -- Richard Hopkins Cardiff, Wales, United Kingdom (replace .nospam with .com in reply address) The UK's leading technology reseller www.dabs.com Out with the old & in with the new at www.dabsxchange.com Get the most out of your digital photos www.dabsxpose.com |
#10
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I knew that was coming ; )
"Richard Hopkins" wrote in message ... "pete" wrote in message .com... I proceeded to lap the IHS then sucked the hole out, with any fine metal particles and compound. Sounds strange but it worked perfectly. ?? Bet it tasted funny... ;-) -- Richard Hopkins Cardiff, Wales, United Kingdom (replace .nospam with .com in reply address) The UK's leading technology reseller www.dabs.com Out with the old & in with the new at www.dabsxchange.com Get the most out of your digital photos www.dabsxpose.com |
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