View Full Version : Lapping the coppermine, to risky?
cyberey66
12-16-01, 08:55 PM
I know the fact that the coppermine has no buffer between the die. When you lap it you're accually lappine the core. Well heres my situation. My cpu really needs to be lapped, it's not flat. The error isn't that great, but my cpu just doesn't seem right. There is only a small part touching and the rest floats. The chooses I have is to either just to sand the heatsinks to fit my cpu or lap my cpu.
Has anyone successfully or unsuccessfully lapped a coppermine CPU? I don't want to go to town, just a very small lap. I already did a very little bit, but I only have one try at it so I figured I'd ask first.
One more thing, I never used artic silver, but my next online order im picking up some. If I used that, will that small error cause much temp difference?
jazztrumpet216
12-16-01, 09:15 PM
Hmmmm... from what I've heard it's next to impossible to kill a CUmine. Even lapping it. However, I've never done it because I don't have the $$$ to buy another CPU in case I accidentally kill one. I have lapped heatsinks though. I find that helps a bit, and that ASII you got should take care of any imperfections in the CPU core. After the ASII, the lapping would only really be a matter of performance, IMHO.
I really want someone to reply to this but I was going to lap me core to although I find it very risky and scared to crush the core !
FrankMasterFlash
12-16-01, 09:21 PM
No, Lapping=Bad:mad: on coppermine cpus. I killed a Celey 600 doing that, I think slake did too. Even if you get it to work again you would only lose tops 0.5ºC. Not worth the risk in my opinion.
Just my 2½¢.
cyberey66
12-16-01, 09:34 PM
yea, i haven't learned to get past the curving effect either. What happened to the huge die from my celeron 433. I lapped that to the copper with near mirror, but still had a slight curve effect. I guess ACII and new cooler is the way to go, but if my CPU doesn't OC then, I'll be either laping or peltiering next.
Originally posted by FrankMasterFlash
No, Lapping=Bad:mad: on coppermine cpus. I killed a Celey 600 doing that, I think slake did too. Even if you get it to work again you would only lose tops 0.5ºC. Not worth the risk in my opinion.
Just my 2½¢.
FORGET LAPPING!
Thank you for your advice LOL.
cyberey66
12-16-01, 09:38 PM
Originally posted by tsunami
FORGET LAPPING!
Thank you for your advice LOL.
Ha, sounds like an edited movie on TV. Hey FORGET YOU man!:mad:
Originally posted by satan
Ha, sounds like an edited movie on TV. Hey FORGET YOU man!:mad:
LOL :)
FrankMasterFlash is right, I did murder an innocent Celly 600 by lapping it. Reading satan (yikes!) and Tsunami's posts reminded me that the seeming curvature of the core is what prompted me to try it. I already replied to Tsunami's post in the cooling forum, but let me say again Don't do it!!!" Besides the Celeron I fear that lapping is indirectly resposible for the premature death of my P3700 which died last week, unable to recover from a power failure.
I would advise against lapping the CPU, lots of folks have ruined their coppermines doing that. That said...I did lap a little bit on my old C-566 because it had a high spot. I used a super fine 1000 grit sandpaper and was very careful. I did not try to get it perfectly flat, I just knocked the high spot down a tiny bit so the heatsink would sit on it better. I used Arctic Silver before and after I did this. The end result was almost no change in temp. However, lapping the heatsink helped a lot. Maybe because the CPU core is already smooth and the heatsink had machine marks on the surface, I don't know. For what it's worth.
ol' man
12-17-01, 08:45 AM
The only true way to tell if the core is a little curved is to use a straight edge. I believe intel gets the silicon cores as flat as it can be but I may be wrong. I have never seen a core be curved. I have seen one IHS be concave as also my PII 233 chips IHS also which I also lapped. I have found if you have a core/IHS that bubbles out a little it is best to use a curved surface to sand with otherwise you will not get the center down level with the rest of the surface. My personal opinion is that lapping the core is a nono. I have heard that they put a coat on the core to make it non conductive cause as you know silicon is a semi conductor. I could be wrong about the coating. My experience is that if your HS bubbles out try and find a surface to put sandpaper on that slightly bubbles/curves out also. This will take down the center first. You also want the curved surface to be linear not simply a bubble. It should be similar to taking a sheet of paper and bending it slightly. It will work for a "bubbled" HS/WB. I used this method on the WB I made. It worked very well.
Here is kind of what I am talking about. It just so happend that I bought a sharpening stone and it indeed had a slight curve to it like the bottom pic shows.
outhouse
12-17-01, 08:54 AM
I lapped my p3 1g with 600 [not much with 600] then 1500 but i was very very careful and like the rest i would not reccomend it. One note i do allot of fabricating and have a good eye for milling i made all of my passes slow and like was said i only got a half a C at best.
Now you guys are starting to make me pee in me pants!
Hehe sounds very dangerous.
ol' man
12-17-01, 06:17 PM
Originally posted by tsunami
Now you guys are starting to make me pee in me pants!
Hehe sounds very dangerous.
Umm dude, don't touch the core:) Are you sure it is curved a little or is it just the HS.
Originally posted by ol' man
Umm dude, don't touch the core:) Are you sure it is curved a little or is it just the HS.
Core looks a lil curved but I guess lapping the heatsink will do.
tainice
12-18-01, 01:56 AM
from what I've heard it's next to impossible to kill a CUmine
Hate to tell u, but i killed a lot of them..... :eek:
Just shoot
12-18-01, 08:46 AM
A year ago or so lapping was the way to get just that extra mhz out of a cpu. Well I hate to say if your not perfest you'll probably get higher cpu temps and have a bigger problem than what you have now. Its a very touchy procedure because its difficult to keep from rocking on the core thus rounding the edges and dome the surface.
You'll be farther ahead using the asII like you said it does a equal jop as a good lap.
ol' man
12-18-01, 11:16 AM
Originally posted by Just shoot
A year ago or so lapping was the way to get just that extra mhz out of a cpu. Well I hate to say if your not perfest you'll probably get higher cpu temps and have a bigger problem than what you have now. Its a very touchy procedure because its difficult to keep from rocking on the core thus rounding the edges and dome the surface.
You'll be farther ahead using the asII like you said it does a equal jop as a good lap.
Not to throw gas on the fire but ASII will never take the place of a very tight gap between the HS/core.
Just shoot
12-18-01, 12:44 PM
I agree 100 % but its so difficult to get it perfect that it doesn't pay.
In the old forms there was numerous debates on this topic, I'm prety sure that the general concensus was just to use AS at that time.
I'm sort've caught in between on this one.
I've lapped both a Celly 600 and PII 700 which I both still own and are running now. Both chips are about 2 years old and do their proposed overclocks (900 for the Celly and 933 for the 700).
As far as lapping for proper fit with the heat sink, I wouldn't recommend it. You will not be able to get enough off to make a difference. There is so little to take off of a CuMine that lapping for that purpose would result in certain death.
As far as lapping for temperatures which can help to flatten out the surface a little bit and also to remove the ceramic layer covering the die I noticed a slight temperature drop but not really enough for the risk if it's not a necessity.
Originally posted by Jon
I'm sort've caught in between on this one.
I've lapped both a Celly 600 and PII 700 which I both still own and are running now. Both chips are about 2 years old and do their proposed overclocks (900 for the Celly and 933 for the 700).
As far as lapping for proper fit with the heat sink, I wouldn't recommend it. You will not be able to get enough off to make a difference. There is so little to take off of a CuMine that lapping for that purpose would result in certain death.
As far as lapping for temperatures which can help to flatten out the surface a little bit and also to remove the ceramic layer covering the die I noticed a slight temperature drop but not really enough for the risk if it's not a necessity.
I figured you'll never be able to make it flat without making it so flat that the heatsink will make no contact at all..
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