lapping the cpu....

[freddie]

i've lapped the bottom of my cooler, but it occured to me the cpu ceramic is pretty rough in comparison.

has anyone lapped their cpu - what are the disadvantages? i'd guess there is a static problem roubing the cpu over sandpaper....

[mildlyAmused]

This seemed to give a pretty good look at what happens before and after you lap your CPU. I think I'll do mine when I get it, 11-15% decrease in temperatures sounds great!

[fat jez]

I got about a 9°C improvement on my temps when I lapped my Q6600.

There is a guy on here called Graysky I think who posted some good picks. Just do a search on lapping and it should turn up his post.

Cheers,
Stephen

[Tetras]

There are some guides on tha interweb, like this one:
http://www.xtremesystems.org/forums/...d.php?t=156774

It does of course void your warranty and the temperature difference/benefit varies depending on how uneven the IHS/CPU is. It usually minimises the variance between cores somewhat even when the overall difference isn't much though.

[iranu]

lol - I once ground (lapped) then polished the copper bottom of a cooler to a 1 micron finish, but then again I do that kind of thing every week or two as part of my job. Makes a big difference having the tools in the lab too.

The extreme systems guide is a very good laymans one. Especially the part about putting minimal pressure on the cpu and turning 90 degrees. Turning it 90 degrees is crucial! Otherwise you'll grind away the side facing the grinding direction faster than the back.

It takes a good deal of time to be able to learn to grind things flat without introducing bevels or grinding one side more than the other when putting pressure on the specimen so the only way for a novice to do it as per that guide, holding the cpu by the sides and be patient.

Tips from a pro.

1. Very lighty wet the surface the grit paper will be on, then place the grit paper ontop. Move the paper around with your hand and then it will suddenly stick to the base. It won't then move about or bend when grinding (and you won't then need sticky tape).

2. Maybe practice the first grinding stage (320 grit) with a piece of metal (brass or copper is ideal) to get used to it. Use something similar in size and shape to the cpu that you can just throw away. Be sure to remove any sharp edges before you start by using the 320 grit paper. Don't use this paper again it will be contaminated with this metal and will spoil the grinding of your soft copper heat spreader. It's easier to keep something flat the less high it is i.e it doesn't wobble.

3. How do you know when to change to a finer grit paper? When you do the grinding after a certain time all of the ginding lines will be in one direction. When that time occurs it's time to go finer. You can see this by holding the lapped surface upto the light. Remember that each grade of paper is removing the scrathes from the last. His 6th photo down shows.

4. After the final grinding stage just moisten the paper with a small amount of water and continue a bit longer. You can now press a little harder. The result will be much better. I wouldn't recommend using water to a novice for all the grinding stages because it will be too messy and it weakens the paper and makes tearing easier.

I laughed my head off when he says, "After 1 hour of lapping on 320 girt Paper" - an hour FFS it would take me 5-10 mins, but that's because I can put pressure on the cpu. I would also be using water with the grit papers making the grinding faster by taking away the removed material, but I'd be grinding on an inclined surface or using one of these


hand water grind on the right - mechanical diamond polish and alcohol lubricant (with a modified specimen holder) on the left.

[Harkin]

Iranu, any chance I cud send you a Q6600 for lapping? Just kidding really( you would have ppl queing up), wish I knew someone with one of those machines though, looks a doddle with it..

[acrobat]

I was about to say the exact same thing...

I would LOVE to lap my CPU but I don't think I could do it myself. For a few reasons.

[Agent]

I wish you could just remove the dam IHS on core2's (reliably!) like you could with the A64 (after a bit of careful work, of course)

[fat jez]

I laughed my head off when he says, "After 1 hour of lapping on 320 girt Paper" - an hour FFS it would take me 5-10 mins,

I think I spent an hour total on mine, including taking the PC apart, cutting up sandpaper and putting it all back together again. Was definitely worth it though, I dropped about 8-10°C full load by doing it!

Cheers,
Stephen

[Thorsson]

What's girt?

[iranu]

Iranu, any chance I cud send you a Q6600 for lapping? Just kidding really( you would have ppl queing up), wish I knew someone with one of those machines though, looks a doddle with it..

TBH I wouldn't use the wheel for hand grinding or polishing without making something to hold the cpu package. Holding onto something so low in height is difficult when the wheel is spinning. All of a sudden you find you loose grip and what ever you are grinding either sticks to the wheel or flies off at velocity in a random direction. Not the best thing for a £165 chip!

[mildlyAmused]

I wish I still had access to the grinding wheel I had in highschool. 2 seconds on that and you've have a very flat CPU. Likely lose your fingers too.

[Kumagoro]

If I had money to burn I would buy a E2140 or new E2180 m0. Apparently the IHS comes off
easy with the E2s. E4300 seems to OC like crap now which seems to have been blamed on the
IHS connection being thermal grease and not the epoxy like on the higher end ones. Or is the allendale
core somehow different and nobled compared to conroe...

[-N!CK-]

if you're weiry about lapping it yourself chilled pc do a lapping service i think

[freddie]

good stuff, i might just try it out on a e2140, going for around £30 in scan according to a post!

i'll probably do this myself -N!CK- it half the fun to get results from doing it yourself! i don't mind trying it out on the cheap processor before i get brave enough for a quad...

[iranu]

I had a look at the chilled pc kit and it seems reasonable value to get all the grades of paper required.

So I decided to lap my Big Typhoon and a new chipset cooler using 400grit to 2500grit DIY stylee to see what results I could get. I found I had to tape the papers down with gaffer tape when using an old bit of kitchen worktop for the base as they slid a bit when using water. I then used some silver polish (old sainsburys own brand) just to see the result and was quite impressed. I got an old lint free cloth then laid that flat on the clean surface and poured on a bit of polish. Using a circular motion and applying a bit of wd40 now and again I actually got a really good mirror finish around the 3µm (3micron) mark. Brasso is not quite so good because you need to filter it and it usually leaves scratches (it will etch aluminium quite nicely though). Protect the surface from further scratches buy getting some cotton wool and taping it to the polished surface if you need to store the item before installing it.

I think aslong as you can hold the cpu in some form of container while lapping then it's easy to do if you are patient. Trying it out on a cheap cpu is a good idea because even if you don't use it you can sell it on easily.