NIKO’s C2D lapping Guide

Although my C2D temps were pretty low I decided to lap my CPU for the sheer hell of it and the experience, gains as good as 4-10C under load have been reported on the net, at the very least I would see how good my IHS is & lower my temps just a little (or even kill it stone dead ;-D ).

 

DISCLAIMER:   If you carry out this procedure you do so at your own risk, however you will have to do something really silly to kill your CPU, SO BE CAREFULL!

 

It goes without saying that doing this will void your warranty for your CPU.

 

TOOLS FOR THE JOB

1 Sheet of 300 Grit sandpaper

1 Sheet of 600 Grit sandpaper

1 Sheet of 1000 Grit sandpaper

1 Sheet of 1500 Grit sandpaper (Optional)

1 Sheet of 2000 Grit sandpaper (Optional)

Lots of cotton Buds

Isopropyl Alcohol

A Processor ;-D

A flat surface, this can be a glass table top or a mirror.

1 Earth strap

 

 

I actually used a removable  cooker door glass panel for my lapping surface, on my cooker they slide out for easy lapping.. Err I mean cleaning.

Also I did not have an earth strap handy so I delved into my junk drawer as you do & pulled out an old 56k Modem phone line cable (I knew this would come in handy one day ;-D ) and snipped the ends off, stripped the wires & connected one end to something earthed near where I was working, a radiator inlet/outlet pipe (bare copper pipe) will do, & connected the other end to myself.

 

Below is the processor I used, it’s a Core 2 Duo E6400 @ 2.13 GHz

 

 

Lapping Procedure:

Lay a sheet of 300 grit paper on your flat surface of choice and begin to lap, I used the alternating cross pattern but it does not really matter how you do it as long as you keep it flat.

 

After a while the copper underneath the thin nickel layer will start to show, as you can see my CPU is not bad at all, its actually up a bit in the middle & at the top.

A lot of people are reporting really bad concave IHS’s, on earlier C2D’s , this is where the IHS is down in the middle, this is bad because it will make for a really bad contact area with the HSF there will be lots of airspace in-between, these are the guys that will benefit most from lapping their CPU.

 

 

As I continue to lap moving up the sandpaper grades you can clearly see the copper coming through everywhere, this shows us that my IHS is actually up in the middle or down at the edges, whichever way you want to see it, take a look at the pictures below.

 

 

I continued lapping with the 300 grit until the nickel was all but gone.

 

 

Nearly there….

 

 

That’s the 1500 grit done with, you can see that the nickel plating is almost gone.. In the early stages I did not bother about the nickel plate that remains to the very outside of the IHS, this is below the level of the top surface anyway and is well outside the area of the core as you can see below, Its not going to cause us any heat transfer problems.

 

 

A Core 2 Duo E6700 with the IHS removed.

 

 

That’s the 2000 grit done with,  The surface is not super shiny mirror like but this is not necessary, you could probably stop at 1000 grit as many lappers have reported, going over 1000 does not really yield better thermal results, you are looking for a flat copper top and that’s it, its just that I like to go over the top!, some lappers also finish things off with brasso but I would not recommend this as I am not sure how any residual chemicals from the brasso will react with the TIM over time & also polishing the top with a rag over your finger is defeating the object of keeping things flat, If you feel the need for a true mirror finish you could always lay out something like a flat viscose cloth on a flat surface, apply brasso to it and shine away lapping style, as in the same way as you lap with the sandpaper.

 

 

2000 Grit is shiny enough as you can see from the picture above, I cleaned up the CPU with the Isopropyl alcohol & cotton buds, take your time with this and make sure you get all the dirt off from both sides, the last thing you want now after all your hard work is metal dust getting where it should not.

I think its time to get the proc back into my rig.. fingers and toes crossed!

Hopefully I wont have a £150 key ring ;-D

 

 

Processor in place.. remember that you won’t need as much TIM now that you’re CPU has been lapped, a lot of people apply way to much.

 

Incidentally I am using an Arctic Freezer 7 pro air cooler (cheers Gitch!), pic below.

 

 

Time for some graphs, I am not expecting a lot of difference from my lapping experience because I know my CPU IHS was good to begin with as you can see from my first sanding pic, the IHS was slightly up in the middle but this is where the core is and most of the heat is generated here as a result.

 

 

 

 

Conclusion & Results

 

The Idle & Load tests were conducted with an ambient temperature of 20c, as you can see from the graphs I only managed to shave of a couple of degrees from my temps, probably the TIM needs a little time to settle to be fair to the results, I am not making excuses here though because I suspected from the very beginning that my gains would only be small due to me being lucky enough to have a good IHS to start with, maybe these later IHS’s are not as bad as their younger siblings, I would say that it is only worth lapping your CPU if your temps are bad to start with say high 60’s & 70 under load, case ventilation is also a very important factor  and my Antec 900 ultimate gaming case is no slouch in this area.

 

Happy Lapping!

 

NIKO   3/07