A coppermine 'lapping' tale.

[Plester]

i have always lapped my chips/video cards in my often misguided quest for more effetive cooling. with the advent of the itty bitty little cumine core, i was hesitant to touch my 650E with anything, let alone sand paper, and i didn't for the 90 day warranty period(this is a cheap OEM slot 1 from a computer fair - but it overclocks like a mutha). then i read something over at http://www.overclockers.com where a guy had lapped numerous cumines with good results. the seed was planted. the catch in my case was the fact that i had a slot 1 chip which makes for tricky lapping. wasn't gonna let that stop me, and after some tentative experiments i settled on a plan and started lapping. well as you P3 owners know, that core is f.cking small, and despite my patience and care i ended up doming the little b!tch, and reducing its ability to shed heat considerably. now before you start labeling me the idiot that i am, i must say that i attacked the high point in the middle of the slug and eventually got rid of it, and now run at 950mhz/1.78v - 39c/full load 29c/mobo(prime95 for the last 18 hours)with a gorb for cooling, and i am no longer beating myself about the head and shoulders. but i strongly suggest that those harboring this notion(and i know you exist) without access to precision instruments, DON'T DO IT.

 

[atomicbomberman]

thanks for the advice... so what the heck did you do again? Wat's lapping?

 

[Jugernot]

Lapping means he sanded/ground down into the copper on the core of his cpu. This usually isn't a recommended practice, but its not that hard to do. I did it to my Celery 366@550 and didn't get a single increase!

 

[AdamK47]

I agree, don't do it! Coppermine caps are already as flat as can be when you buy them. I lapped my heatsink though. I have the pure copper HedgeHog heatsink on my 650. I have the combo running at 1021MHz with 1.8V.

Edit: I mean all copper heatsink. It's not pure copper, since it's only industrial grade copper.

 

[Eug]

Hmmm... My Celeron II was ultra flat anyway.

Lapping makes sense theoretically but for the vast majority of people it probably will do no good. I always say if you really want to fine, but liquid cooling and lapping are going overboard for a PC.

Plus, my guess is that Arctic Silver without lapping is better than standard thermal paste on a lapped chip.

(By the way, my air-cooled non-lapped Celeron 533A did 960 MHz for several days at 100% load, including OGR, games, 3DMark2000, etc. before locking up once. And only once - ran it for a while longer at 100% load before I reduced it again. Admittedly, I too am going overboard with a copper-endowed Alpha, Arctic Silver, and 1.9 V.)