Lathing, Sanding, Smoothing...CPU

[Gasoline]

I think that getting the surfaces absolutely mirror-like reflective smooth is just a bunch of bling, and if you've got the time and motivation to do all that work, then great.

But however putting just a little effort into getting them at least flatter and smoother to the touch / fingernail scrape than they come stock, is very beneficial.

My new 2.4a (I'm a cheapskate), oc'ed to 3.36G northwood had mild ridges near the four corners and spending just half an hour with some 1500 grit "Micro Mesh" emery cloth & polishing compound to remove the ridges and get the thing noticeably smoother to the touch, resulted in at least a 2-3 degree drop with my Thermalright SP-94 heatsink. I didn't bother with lapping the SP-94, since out of the box it was so smooth I could almost see a good, but fuzzy reflection in it.

 

[Exempt]

been a while since I dropped back in this thread, but basically I guess I should interate this, When I lap the CPU heatsink or IHS, I am not doing it to a mild degree, Im actually taking like 3/12 of an inch off there (srry Im horrible at measurements and converting fractions), but basicallly in a simple analogy, lets take two people that want to transfer heat from one hand to another, and I put a block of metal in between their hands, obviously its common sense and common laws of thermodynamics, that the less metal in between their hands, the fast heat will transfer from hand to hand, with the metal block going from 8" in between to 3/4 of an inch, the heat transference is almost immediate. the IHS is installed on the Intel chip in order to prevent the CPU that is underneath it from being crushed or damage, and in the mild transferrance of heat, its why it is made of copper then coated. If your an HSF cooler/overclocker, then I say sure its worth it, if your a water cooler guy, it might help in the smallest degree, if your a Vapo cooler you dont really need to do it ( although I still do ) It takes about 30 min, and really, its up to the user

 

[Gasoline]

Wow! Removing a bunch of metal off the top of the chip's heat spreader is extreme! But it does indeed make sense. I never though of it that intensely, I was just only thinking to get the surface imperfections flattened out more for better heat transfer between the two surfaces. A thinner heat spreader sure would get the heat xferred more quickly from off the chip's core.

 

[NewBldr]

been a while since I dropped back in this thread, but basically I guess I should interate this, When I lap the CPU heatsink or IHS, I am not doing it to a mild degree, Im actually taking like 3/12 of an inch off there

I know you don't mean 3/12 of an inch... that's 1/4 inch and a cpu isn't even that deep (excluding pins)

 

[Dukemurmur]

hmm lol yeah tacking it down to the pins egh? (jp man ) but lapping really does help.

 

[beau_zo_brehm]

hey, is lathing and sanding really worth it? it looks innexpensive but maybe risky for just your average OC'er.....

 

[magick_man]

well a while ago i did this on my 2.4c and i lost 3 degrees with aircooling
but i just replaced my 2.4 with a 3.0E and the top of that thing is horribls, it looks like it is a concave (outer edges higher than the inner part) surface and the finish isnt that good either.
i wish i could lap the crap out of it but unfortunately it is a retail cpu and i dont want to void my 3 year warranty

~Magick_Man~

 

[Exempt]

my head screams, "void! void! void!"...

but then again, depending on cooling, its sometimes not worth it.

 

[bounty29]

Ok, all this talk of not wanting to lap the IHS because they dont want to void the warranty... you are planning on overclocking, aren't you? Doesn't that void the warranty? And everyone striving for a mirror finish, take a look at this...

Theres your mirror finish from the figure 8 or circular lapping, and your non-mirror finish from single directional lapping. Now look at these...

Mirror Finish -
http://www.employees.org/~slf/flat/grid1.jpg

Non-Mirror Finish -
http://www.employees.org/~slf/flat/grid2.jpg

This just shows that super-reflective does not equal super flat.

These pictures were taken from a thread by Cathar, all credits go to him. The thread can be found here. Now I know that these pictures are of heatsinks, but it's the general lapping method I'm talking about.

Edit: Answered my own question.

 

[Exempt]

you woulndt want to remove the IHS completely, although I have heard of it being done before, its not only there to act as a heatsink, but also for protection of the core. The core is very fragile and is a glass like material, and easily crushed and/or cracked...

here is a recent sanding/lathing/polishing job I did:

http://server6.uploadit.org/files/exempt-SilverHS1.jpg

 

[Revolt26]

For those of you who take the time to lap in and make flat contact surfaces true more power to you. I did mine and it shave nearly 24c off my temps.

I'm sure alot of people think this kinda stuff is perfectly true straight outta the box ...

 

[Wiggins]

I removed the heat spreader from a P4 2.4 (with a razor blade) and the goop between the cpu and the heatspreader is the reason there would be any heat transfer problems, not the heatspreader itself. The goop was cheap and covered the cpu acting as an insulator. I threw the cpu back in using a thermalright copper heatsink with screw mounts (with springs) and it worked fine and didn't crush the core. After that, the heatsink got really hot, which is excellent as you want the heatsink hot, not the cpu meaning the heat transfer is working without any lapping of any kind...I'm not sure I would recommend doing this with any heatsink other than one that has springs between the screw and the mounting hole.

I don't believe in heatspreaders anyways...

 

[Thomas Olivaux]

Excellent job I don't know yet if those mirror perfect CPUs and heatsinks are just beautifull or if it really help for cooling, but I'll try soon Can I expect this type of finish only with water 600? I ask that because I don't have more at home to start right now

Bye,

Thomas

 

[Thomas Olivaux]

I have a waterbloc fixed with 4 screws and spings... what's the best betwin sanding my CPU or removing the heatspreaders!?

Thx

 

[Sneaky]

i just lapped my 3.0 P4 oc'd to 3.83 and shaved 2ºF off my idle temp from 89ºF to 87ºF

and thats only with freshly-applied AS5 - i'm gonna wait a week and see how low it drops when the AS5 has had its break-in period

 

[kb9skw.net]

I got a 3.2GHz Northwood on the way I plan on doing this to, all the way down to the copper. Best sandpaper I got is 1500 grit. Should take a few degrees off.

 

[BigDan3131]

doing both is best

Lapping is a good way to reduce temps,I can say from experience that figure 8ing it might work.But when working soft metals or paint that one direction is best for the rough paper ( 400,600 ) after that two diff directions will cut it evenly with the finer papers ( 800- still a hair rough,1000,1200,1500 and 2000) all done wet to provide ease of cutting.You can get even finer paper now all the way up to 3000.I use two cutting compounds to get my mirror finish without a single line or mark left in it. I use a buffing wheel mounted to a shaft.( yeah I know you dont all have those tools) Im a custom painter so I need them.

 

[9mmCensor]

For those of you who take the time to lap in and make flat contact surfaces true more power to you. I did mine and it shave nearly 24c off my temps.

I'm sure alot of people think this kinda stuff is perfectly true straight outta the box ...

Ok. No way you can contribute a 24c temp drop to lapping.

Motherboard temp reporting is WILDLY INACCURATE, and cannot be trusted.

 

[outhouse]

im old school yada yada ya i lapped a 1g p3 when everyone said no but yet i had a small gain with air cooling [glad i did]

as far as lapping the whole idea behind a figure 8 is that you wont make it unlevel but it does round the edges off a little quicker, the only bad thing about one way is it can make level but in what direction is flat? anytime you do this by hand its an art at best and if your messin with a cpu take your time think things through before you start. I use both 8 first and back n forth [hey its just me youll learn your own stlye] i practiced on many heatsinks from the NB to video cards before i jumped in and grabbed a p3.

I just got a new 3.2 and soon i will lapp away once im sure this is the chip i will own.

with these new intel cpu,s i see copper to copper being a benefit.

 

[Sneaky]

i just re-lapped my 3.0E's IHS to 2500grit
(sorry for fuziness in pics - macro function on my camera does that at times)


edit: the IHS is mirroring my desk shelves about 2 1/2 feet above the desk surface that the processor was lying on