What is cpu lapping?

covert24

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Feb 24, 2006
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when you polish or flatten the bottom of a processor or heatsink by sanding it with gradually higher grits until it gets to a smoother surface than before. also may be sanded to a mirror finish if desired.
 

covert24

Golden Member
Feb 24, 2006
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well since most all cpus are not perfectly flat n the Integrated heatsink (IHS) lapping flattens it producing a flatter surface to provide better heat transfer between the heatsink and cpu. thermal paste only fills the microscopic imperfections.
 

imported_wired247

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Jan 18, 2008
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it is generally not worth your time or effort, and it is not at all unlikely that a first timer will destroy his/her CPU.

it is not *entirely* pointless as it *can* produce a measurable difference in CPU temperature, typically 1-2 degrees C. however, it is ALMOST entirely pointless for about 99.99% of users
 

covert24

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Feb 24, 2006
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Originally posted by: wired247
it is generally not worth your time or effort, and it is not at all unlikely that a first timer will destroy his/her CPU.

it is not *entirely* pointless as it *can* produce a measurable difference in CPU temperature, typically 1-2 degrees C. however, it is ALMOST entirely pointless for about 99.99% of users

theres many that would disagree with you on that one. unless all IHS' are perfectly flat then im pretty sure it will help out a lot more people than you think.
 

crapfest

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Nov 26, 2007
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Originally posted by: wired247
it is generally not worth your time or effort, and it is not at all unlikely that a first timer will destroy his/her CPU.

it is not *entirely* pointless as it *can* produce a measurable difference in CPU temperature, typically 1-2 degrees C. however, it is ALMOST entirely pointless for about 99.99% of users
Not true. I got a 15°C drop in load temperatures after lapping. It even helped me get a better OC.

The thing about lapping is that if you do it slowly and correctly, there's not much risk involved. If you get impatient and start doing stupid things then that's your own fault.

And yeah, as others have pointed out, the main purpose of lapping is to make the IHS and the heatsink base as perfectly flat as possible. The mirror shine isn't necessary (but it does look cool) - the most important thing is making sure that the two contact surfaces are flat.
 

imported_wired247

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Jan 18, 2008
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Originally posted by: crapfest
Originally posted by: wired247
it is generally not worth your time or effort, and it is not at all unlikely that a first timer will destroy his/her CPU.

it is not *entirely* pointless as it *can* produce a measurable difference in CPU temperature, typically 1-2 degrees C. however, it is ALMOST entirely pointless for about 99.99% of users
Not true. I got a 15°C drop in load temperatures after lapping. It even helped me get a better OC.

The thing about lapping is that if you do it slowly and correctly, there's not much risk involved. If you get impatient and start doing stupid things then that's your own fault.

And yeah, as others have pointed out, the main purpose of lapping is to make the IHS and the heatsink base as perfectly flat as possible. The mirror shine isn't necessary (but it does look cool) - the most important thing is making sure that the two contact surfaces are flat.


Sounds like your cooling solution before lapping may have been somehow gimped. Too much thermal compound, micro air pockets....

Of course it can help achieve a higher OC.

By looking around at AT forums or other OCing forums you might be inclined to think "who DOESN'T OC?" but it's really the vast minority.

I knew my comment would open a big can of worms.

And I apologize, I meant to say "the difference between a good thermal contact and a mirror finish is about 1-2 degrees C typically" not the difference between stock and totally lapped
 

Rodknock

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Nov 13, 2006
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Originally posted by: crapfest
Not true. I got a 15°C drop in load temperatures after lapping.

That seems rather unbelievable. Was the original surface shaped like a soccer ball or something?
 

tallman45

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May 27, 2003
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As a first time, make sure the system actually works first before you start lapping

Then, go at the HSF in earnest, I mean really go at it, if you mess that up is a minor replacement cost. When done reinstall and measure the difference
 

PCTC2

Diamond Member
Feb 18, 2007
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Originally posted by: wired247
it is generally not worth your time or effort, and it is not at all unlikely that a first timer will destroy his/her CPU.

it is not *entirely* pointless as it *can* produce a measurable difference in CPU temperature, typically 1-2 degrees C. however, it is ALMOST entirely pointless for about 99.99% of users

I would have to disagree as well. My IHS is curved to hell (concavely) and I've had problems with all HSFs having good contact. I would probably gain a lot from lapping but I cheated and bowed my waterblock. A lot of people get a lot better contact from lapping when starting with a concave IHS and a semi-flat HSF to both lapped. It makes a difference.
 

imported_wired247

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Jan 18, 2008
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case in point... people who have spent the time and effort lapping and overclocking recently will claim it is worth the effort, because if they do not claim it so, then they feel they have wasted their time.

If you are not pushing the limits of what's OCable and you are using a decent thermal compound, there is absolutely no need for the vast majority of users to take any abrasives to their components.



As someone who has lapped and OC'ed in the past, I'll have to say again that it's really not all that magical.

 

Tempered81

Diamond Member
Jan 29, 2007
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2 days ago a guy here had 23c drop under load after lapping. of course his first hsf seating was pretty 'tarded
 

LittleNemoNES

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Oct 7, 2005
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Originally posted by: wired247
case in point... people who have spent the time and effort lapping and overclocking recently will claim it is worth the effort, because if they do not claim it so, then they feel they have wasted their time.

If you are not pushing the limits of what's OCable and you are using a decent thermal compound, there is absolutely no need for the vast majority of users to take any abrasives to their components.



As someone who has lapped and OC'ed in the past, I'll have to say again that it's really not all that magical.

If your CPU IHS came shaped like a canoe (as was mine) you would not be saying this.

Lapping has its place; only you can decide if the benefits outweigh the risk.
 

BonzaiDuck

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Jun 30, 2004
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The thickness of the IHS or processor cap was always a concern of mine. The structural integrity of the IHS was also a concern.

But recently I lapped the IHS of an E6600, just to get it flat.

The IHS apparently has a copper layer covered with nickel plating. This isn't different than ThermalRight's heatsink bases.

Copper his higher thermal conductivity and lower thermal resistance than nickel. I only suspect that you get a great improvement in temperatures just by flattening the nickel layer, but you get another increment of improvement by lapping to bare copper.

I use latex surgical gloves when lapping the processor, and everyone says to make sure you don't get the contacts on the opposite side from the heatspreader wet. It doesn't take very long. I ground it down with 400 wetordry, and then put it on some 600-grit for a little while.
 

Idontcare

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Oct 10, 1999
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Originally posted by: BonzaiDuck
The thickness of the IHS or processor cap was always a concern of mine. The structural integrity of the IHS was also a concern.

But recently I lapped the IHS of an E6600, just to get it flat.

The IHS apparently has a copper layer covered with nickel plating. This isn't different than ThermalRight's heatsink bases.

Copper his higher thermal conductivity and lower thermal resistance than nickel. I only suspect that you get a great improvement in temperatures just by flattening the nickel layer, but you get another increment of improvement by lapping to bare copper.

I use latex surgical gloves when lapping the processor, and everyone says to make sure you don't get the contacts on the opposite side from the heatspreader wet. It doesn't take very long. I ground it down with 400 wetordry, and then put it on some 600-grit for a little while.

Surgical gloves are entirely uncessary but the peace of mind can be priceless.

I use bare hands. Surgical gloves protect YOU from whatever you are touching, it doesn't protect whatever you are touching. You'll still deliver just as much static shock with or without those gloves, and whatever you do touch while wearing those gloves will still eventually end up getting onto the CPU as you handle it.

Water on the contacts is bad? You'd think so but it really does not matter. I've had my chips so wet they were literally dripping. Water does nothing to gold, nickle and barely ever so slowly will tarnish copper. The problem with water on electronics only comes when there is a voltage applied. So make sure the suker is dried out before plugging it in. (rinse it in isopropyl and dry).

I use to be really paranoid about killing my chips, then I got into vaporphase cooling and learned over the course of year that motherboards, sockets, and chips can actually handle an exceptional amount of water exposure and just keep on ticking.

The concern to have with water when you lap your IHS is that the water (or any liquid you might be using) can carry metal filing fragments into that little hole on the side of the IHS and from there those metal filings can become lodged under the IHS but short-circuiting something important. I have not heard of a single person ever actually killing their chip from lapping in this manner, but the paranoia exists nonetheless.
 

Markfw

Moderator Emeritus, Elite Member
May 16, 2002
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Originally posted by: gersson
Originally posted by: wired247
case in point... people who have spent the time and effort lapping and overclocking recently will claim it is worth the effort, because if they do not claim it so, then they feel they have wasted their time.

If you are not pushing the limits of what's OCable and you are using a decent thermal compound, there is absolutely no need for the vast majority of users to take any abrasives to their components.



As someone who has lapped and OC'ed in the past, I'll have to say again that it's really not all that magical.

If your CPU came IHS came shaped like a canoe as was mine, you would not be saying this.

Lapping has its place. You should decide if the benefits outweigh the risk.

I also know for a fact is can have a BIG difference (10c at least)

I think there is enough evidence that lapping can make a big difference that you need to give in to the majority that disagree with you. And the experience level of the people who say it makes a difference also makes your claims loose credibility.
 

BonzaiDuck

Lifer
Jun 30, 2004
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Well, so much for my folklore confusion over the gloves and water. I never noticed a hole in the cap -- as with the socket-478 processors -- though.

What's been the temperature-reduction experience here if you don't lap off all the nickel-plating? I only lapped my IHS so it was flat, and no copper exposed. Graysky had a post on another forum with pictures regarding his C2D or C2Q lapping experience, and he'd lapped off all the nickel down to bare copper. No folklore -- that the copper has better thermal conductivity . . . .
 

BonzaiDuck

Lifer
Jun 30, 2004
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Soo . . . . I see the copper on PhunkOne's masterpiece . . . .

What's the experience with lapping that leaves the nickel-plating intact?
 

covert24

Golden Member
Feb 24, 2006
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probably little to no difference. i would think that when you lap it, it gets the heatsink closer to the actual cpu itself (even if its only by a couple mm/nm) so as to give a more direct contact. i have no idea if that would make that much of a difference but yea. oh and also it wouldn't look as good :p