Buying a delidded CPU

[flamery]

Hi guys, I got offered an 8700K delidded with IHS lapped.

I only know a tiny bit about delidding, so my understanding means that the top cover has been removed, and the die has been polished is that correct?

I currently own a hyper evo 212 cooler which I would want to re-use, do I basically just apply my artic silver to the top of the die and plunk the cooler straight on top of it? I assume I just leave the IHS off. Is there anything else I would need to do?

 

[CountMike]

No, nothing is polished only the paste between lid and core is changed to more efficient one. Lapping/polishing of top of the lid can also be beneficial. If you want to go to all that work/expense than you should also go for much better cooler.

 

[Karadjgne]

Seems Intel is only focused on putting out a quality cpu, but only gets the job ½way done. The paste used between the IHS and IC seems to have been installed by a blind chimpanzee. Has been this way since the switch from soldered IHS to paste with Ivy-Bridge lga1155. Consequently, temps per core are always funky with averages around 10°C between hottest and coldest cores and a hotter running cpu. So ppl took to de-lidding, where the monkey crud is removed and a higher quality, more efficient and cleaner installed paste is used to replace it. Correctly (you hope). End result is a general evening out of the temp variances and a slight lowering of temps across all the cores. This doesn't affect the IHS in any other way. You still see the Intel factory print on the IHS surface.

Lapping/polishing is different. Can be done on either unlidded or delidded cpu. Because of manufacturing, the IHS is never perfectly flat, it's got a slight bow in the middle, making external paste thicker generally in the middle. Common theory is if you polish/lap the IHS surface, basically grinding it down to flat with sandpaper, you'll get a better, flatter, more even compression of the external paste to the cpu cooler. The result if done right is an almost mirrored surface to the IHS, however, this process totally destroys the factory print and invalidates any warranty or possibilities of guaranteed identification. It's quite often done to engineering prototype cpus which are illegal for sale if identified as they are Intel property that's basically stolen. So don't buy lapped/polished cpus unless you know for a fact the history of the cpu.

1. Don't bother with AS5 it's a very mediocre paste to start with and needs to be often replaced as it only has a 200ish thermal cycle (from cold to very hot) averaging a yearly change on OC cpus.
2. No, you absolutely need the IHS or the distance from cores to cooler is changed and any paste used totally bunks up the cores themselves making cleaning old paste impossible.

 

[volkgren]

You can use AS5 on top of the IHS in between your cooler, but don't use AS5 underneath the IHS in between the die, it will semi-work for a day or so but will run out and temps will become too hot. I've done this for a few days until I got liquid metal in the mail.

I used Thermal Grizzly Conductonaut and was more than satisfied with the 20C drop in temps from non-delidded. I hear Coollaboratory Liquid Ultra is almost as good as Conductonaut.

With liquid metal you will want to take extra precaution and not get any anywhere except the CPU die and the IHS.