So I had a go at lapping my CPU. (For those that don't know, lapping is sanding and smoothing the heat spreader on a CPU.)

Materials used-
Alcohol
Sandpapers- 400, 800, 1000, and 2000 grit
Double sided tape
Cotton swabs and balls.

Preparing the CPU for lapping-




Nickel plating starting to wear off and show the copper (It's blurry, so you will have to look hard, sorry)


Copper completely exposed (Blurry yet again)


Finished job after polishing with 2000 grit


Brought my idle and load temps down about 6 degrees. I didn't bother lapping the heatsink because it's a pile of junk anyway.

I was thinking of doing that, but I'm really, really scared of messing it up. Is it really even possible to do this wrong? I'm assuming the heat-spreader is thick enough that you can't sand THROUGH it, lol.

I'm more concerned about it being uneven when it's done.

Quote from Stang70Fastback :

I was thinking of doing that, but I'm really, really scared of messing it up. Is it really even possible to do this wrong? I'm assuming the heat-spreader is thick enough that you can't sand THROUGH it, lol.

I'm more concerned about it being uneven when it's done.

It's not really hard if you set up your "workstation" right. Do what I did- tape the sandpaper to a flat, sturdy surface. I used double sided tape, about a millimeter thick, so I had to line about 5 pieces of tape up to lay each piece of sandpaper on. A piece of glass will also work as a base for keeping sandpaper flat. If you have any old CPU's laying around, practice on them first. Also, you can find the grades of sandpaper needed in an automotive store or the automotive section of a place like Wal-Mart.

Wait, so what you did was tape the sandpaper down and then rubbed the CPU on it? I'm seriously considering doing this with my FX-62 now, but I'm still a bit tentative.

keeping it absolutly flat is far more important than making it polished and reflective! When lapping you can tend to overdo the edges.

I've read you should moisted the sandpaper and stick it to a (horizontal) mirror, so that it will remain almost perfectly flat.

I'm assuming there is reason for the nickel plating? Can sanding it off potentially cause any long-term issues?

Quote from Bob Smith :

I'm assuming there is reason for the nickel plating? Can sanding it off potentially cause any long-term issues?

copper + air = bad

Quote from Shotglass :

copper + air = bad

Don't you mean copper+water? Or am I missing something?

Copper will corrode eventually, though you can doubt noticing any of that in a heatspreader / thermal goop / heatsink arrangment for a few years..

Quote from h3adbang3r :

Don't you mean copper+water? Or am I missing something?

Air contains water vapour.

The nickel is for longevity, but most people who do this sort of mod are the people who will throw away a system when the next new piece of hardware comes out. If you don't want to lap it, you can run it naked (read: remove the heat spreader), but when you do this, just with older chips, you have to be careful when applying the heat sync so not to crack the core.

And the FX-62 might be soldered so you wouldn't gain much. It was very popular to pop the old s939 because the IHS and core contact was VERY poor most of the time.

hey stang, i saw you`re thinking of lapping the ihs, but are a bit afraid not to sand through it.. well, i saw some folks completelly removing the ihs(1,2) yielding some great results.. 43~degrees full load.
some "complained" that they experienced a drop from 55 to 42-43deg full load(up to 20degrees on water cooling-insane).
in this removal video, he plays it safe. but others.. are quicker.

you can also see how "thin" the IHS is, so.. i wouldn`t worry .

Quote from Primoz :

It was very popular to pop the old s939 because the IHS and core contact was VERY poor most of the time.

i have a venice 939, and my idle temp is 45-47, full load 54~58. i clean it up regularly(take it apart once every 1-2 months), cooling is good, i guess my problem is up there in bold ^.
i`ll play it safe, only lapping it+hs, have them nice an shiny.
one planning to completelly remove ihs, must be ready anytime to.. buy another cpu, IF he screws up.

Yeah, cracking a core on Athlon XPs really wasn't a problem compared to naked s939/AM2s/LGA775s and it actually WAS a problem back then. SO yeah, a BIG problem. The thing is these core are 'bare', Athlon XPs had a protective layer over them reducing the chance of a chiped corner. A bolt mounting mechanism is a MUST if you pop the IHS. I have an unused 3000+ Venice in the closet behind me, i can try to pop it if anybody wants... Could sell it for 20 € but it's not worth it i think. I'd rather make it a key chain ornament.

Quote from STF :

(take it apart once every 1-2 months)

That is bad for cooling, the TIM needs time to cure, which can take up to 1 month to yield optimum heat transfer, as such you get better temperatures.

http://www.xtremesystems.org/forums/showthread.php?t=134895

If you want to know for sure, cut the rubber - if the IHS falls of, it's not soldered. Apply some TIM (i wouldn't put AS5 there, i'd put some Ceramique there) and put the IHS back on if you want to be sure (with some black bathroom sealant or something like that. If you have the guts, run it naked.

Quote from Primoz :

Could sell it [..]but it's not worth it i think. I'd rather make it a key chain ornament.

good for didactic material, and would add some good pictures to this thread.

Quote from P5YcHoM4N :

That is bad for cooling, the TIM needs time to cure, which can take up to 1 month to yield optimum heat transfer, as such you get better temperatures.

i sometimes forget about it for almost 6 months.. and when i do remember.. it`s because it starts making noise, it`s getting clogged with dust, becomes inefficient and fan rpm increases(:schwitz. i guess i could vacuum it.
anyway, i`ll take it apart soon.. (been ~2-3months now). this time > lapping.

Vacuum or blow the dust out of the IHS with a compressor. It doesn't have to be removed. But remember to use VERY small rpessures (~1 bar) if you use a compressor since higher pressures could blow a small SMD off and then it's bye bye hardware.

EDIT: it's a LBBLE 0519DPKW. I have 2 olfa cutters here and they are both too thic. Looks like i'll have to get some razers. And a NF4 and 2x512 MB RAM setup