Lapping the DIE???

[mbigna]

I have been reading this forum and have seen lots of advice for smoothing out the heat sink before application to the CPU. I was curious if anyone has already discussed or performed lapping on the CPU die? It seems to me that even if the heat sink is perfectly flat, temperatures would be more affected by imperfections in the surface of the CPU.

Other than losing the information printed (etched?) on the die, are there other problems with this idea?

The die is too thin?
The die is too fragile?
Possibility of debris in the CPU?

[chuckchippie]

NO DO NOT LAP AN EXPOSED DIE! Do not lap an AMD Die it WILL kill your chip...lapping a die is for something like a celly or a P4 (maybe)

[Twinkle]

if you go too far Id like to know how you would explain it to the RMA department.

[Colin]

Originally posted by chuckchippie
NO DO NOT LAP AN EXPOSED DIE! Do not lap an AMD Die it WILL kill your chip...lapping a die is for something like a celly or a P4 (maybe)

chuckchippie - I have watched your knowledge progress as you ask questions on various forums. While lapping the die is hard core, it is not death for an AMD CPU. I don't recommend it for obvious reasons but please don't make such a blanket statement on process you have not tried.

I have done it with success using 2000 grit and checking the progress every 15 or 20 seconds with a 20 power loop. I only went far enough to remove the etching. If you see copper, you loose. Not recommended for the faint at heart or those who cannot easily afford a new CPU. FWIW, I have not lapped the last few Birds I have purchased. Super cooling with pelts makes the 2C advantage of lapping the chip one of diminishing returns.

[chuckchippie]

Originally posted by Colin


chuckchippie - I have watched your knowledge progress as you ask questions on various forums. While lapping the die is hard core, it is not death for an AMD CPU. I don't recommend it for obvious reasons but please don't make such a blanket statement on process you have not tried.

I have done it with success using 2000 grit and checking the progress every 15 or 20 seconds with a 20 power loop. I only went far enough to remove the etching. If you see copper, you loose. Not recommended for the faint at heart or those who cannot easily afford a new CPU. FWIW, I have not lapped the last few Birds I have purchased. Super cooling with pelts makes the 2C advantage of lapping the chip one of diminishing returns.

well thanks...and thanks for setting me straight...

[Christoph]

Sounds very hard core. I'd call it insane, but I just killed a CPU, so I've got a strong bias against playing with the die.
Colin, did you get any better results? Sounds like a good thing to do right before an upgrade.

[ken257]

With AMD P3 and C2 there is really no need to lap. The gain is small and not worth taking the chance of killing your chip if you are not sure of what you are doing. However with the old celerons when they were .25 micron lapping gave very good results this is because they were often far from flat. On my old BP6 with dual 366's one of the cpu's was so bad that when you set the HSF on it only the 4 corners made contact. Light could be seen between the HSF and CPU over the entire surface. needlas to say laping gave incredable results on this one.

[el]

aren't you lapping the bottom of the core anyhow since it is a flip chip so it would be safe but I don't recommend doing it.

[ve6jhc]

You have to be very hard core to even think of lapping the die!!

[Monaco]

I agree, modern cores are just too fragile for me to want to risk it. I used to do it to older chips, like my 300A but not the new ones. I like IdeaMagnate's point- I'll do it when an upgrade is on the way!:)

GPUs, however, those I lap the crap out of. :D

[*spazzed*]

Originally posted by IdeaMagnate
Sounds very hard core. I'd call it insane, but I just killed a CPU, so I've got a strong bias against playing with the die.
Colin, did you get any better results? Sounds like a good thing to do right before an upgrade.
Why don't you lap that blown chip? That'll give you some experience as to how thick the layer is on the die......