EggXpert

I did this a few moths back but figured I'd share with you guys. :)

So I lapped my CPU and heatsink. Enjoy the pictures. Results at the bottom of this post.

















Both CPU and Heatsink were lapped first with 800 grit, during which the CPU was found to be concave as was expected. It was then fine-sanded with 1500 grit, and buffed to a shine without using any solvents; just a clean rag. The same was repeated for the heatsink. The heatsink was terribly coarse, and cutting lines could be seen clearly on the copper base.

Entire project time was about 2 hours not including the shopping for sandpaper or taking the computer apart. A very very thin layer of Arctic Silver 5 was then applied onto the CPU alone before re-installation.

Current stable overclock is at 3.5GHz (Core 2 Duo E6600), at an insane 1.472 volts (from 1.325V stock). This CPU doesn't overclock very well AT ALL, but it does once you crank the voltage.

Initial tests with two instances of Prime95 before lapping both resulted in temperatures of 72 degrees C on both cores, reported via Intel TAT (Intel Thermal Analysis Tool, equivalent to CoreTemp).

After lapping the CPU and heatsink, temperatures under full load dropped to 58 degrees C on both cores, which yields a temperature drop of an incredible 14 degrees C.

I doubt anyone will do this, but if you're interested in having your CPU/heatsink lapped by me, send me a PM and I'll let you know what I'd charge to do it.

Note: Since this writeup I've reduced my clock speed from 3.5 to 3.33 and lowered voltage to reduce power consumption. 

Very impressive.  For anyone thinking of following suit, I recommend you only buy OEM processors which do not have a manufacturer's warranty, and come with only  the retailers return policy of typically 15 to 30 days.

Because the moment you start to lap your CPU a retail processor's warranty is void. 

So, you can lap your heat sink right away -- though that also voids the manufacturer warranty, and the retailer doesn't want it back either...but it is cheaper than a high end processor..  But save the CPU until the retailer's return passes. You can do your overclocking and testing up until then.   Then have at it.  Just a suggested plan. 

Well, if you look under those incredible photographs you will see his instructions for what he did.

Lapping is grinding off the upper layer of the processor and heat sink contact areas to level them out and remove any pits and imperfections.  This creates a mirrored image.   

This nets you a increase in thermal conductivity to lower your CPU's temperature and create a more uniform heat transfer across the surface area contacting the CPU and the heat sink.  You also use much less thermal compound to join the two together.

You void the warranties from the manufacturers of the CPU (if any) and the heat sink.  As well as any chance at return to a vendor.  So you want to make sure they are fully functional or you do not care about the loss of money before you start.

RocketScientist:

I was considering doing this myself. Now that I know that it will actually get noticeable results I might try it. It'll take me longer than two hours because I'll give the same quality that I do with optical prototypes at work. I have access to nice polishing stuff at work, such as 50,000 grit diamond powder and nice polishing pads.

Nice! Just make sure you're getting a flat surface, not just a shiny polished surface. The whole point of the laps against a sandpaper taped to glass is to get a perfectly flat surface, which is much more important that the polish.

XtremeRevolution:

Nice! Just make sure you're getting a flat surface, not just a shiny polished surface. The whole point of the laps against a sandpaper taped to glass is to get a perfectly flat surface, which is much more important that the polish.

I agree.  The surfaces being flat is much more important than a mirror finish.  I found the copper CPU cover to be very low in the center and/or very high on the edges.  It took me the bulk of my time to flatten it out with 400 grit sand paper.  If RocketScientist uses the type of equipment and polishing compound he stated then he may not even need thermal compound.

Hey X.R.!

I believe we talked about this some months ago, you've done a very nice job of it. 14 degrees,,,,, I haven't followed this forum and don't offer help much anymore because of all the naysayers and fanboys but do browse once in awhile. In another thread you reffered to this and I had to respond, a big kudos to you man, nice job.

This should be stickied......

WoodButcher:

Hey X.R.!

I believe we talked about this some months ago, you've done a very nice job of it. 14 degrees,,,,, I haven't followed this forum and don't offer help much anymore because of all the naysayers and fanboys but do browse once in awhile. In another thread you reffered to this and I had to respond, a big kudos to you man, nice job.

This should be stickied......

I wouldn't mind updating this thread with more detailed information on exactly how the lapping was done if it would get stickied. 

XtremeRevolution:

I wouldn't mind updating this thread with more detailed information on exactly how the lapping was done if it would get stickied. 

If you keep it up to date I will sticky it for about 6 months if that is ok as long as you follow up on it and question people may have in the future.

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OK just put a sticky on it for 6 months.

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