jmke

proof baby. I dont think the difference between 1200grid and 2500grid will account for 2°C temp drop.

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Sidney

Getting interesting day by day......

1200 already enough to make it mirror like finish; 2500 will make it feel like a baby's *** smooth. Making a 30-45 minutes lapping job into days of rubbing with 2500 grit.

I thought the purpose of John's article was about less extreme. Considering 100% perfect condition; the TIM is 0.05-0.08 C/Wl it would be like running faster than your own shadow.

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lazyman

Opteron 165 (2) @2.85 1.42 vcore AMD Stock HSF + Chill Vent II

insulglass

Disclaimer: I sell more lapping kits than everyone else combined in the world.

Having said that, there are probably some points to address:

1) JMKE, in my humble opinion, you only did half-a-job. Lapping a CPU will typically only provide 25% of the thermal improvement by lapping. The biggest advantage will come from lapping the heat sink, which is far likely to be manufactured to lower finish tolerances. This is even more exaggerated by AMD processors with die exposure.

2) in my humble opinion, you did not lap through the available grit ranges. While the majority of improvment from lapping does occur at P100-P1200, there IS marginal improvement by lapping to P2000 and beyond.

3) Even though YOUR particular improvement was only 1C, other people may experience more. A drop of 2-4C is average, with many people reporting even more. A 1C drop is actually fairly rare, and I have experience from customer feedback from thousands. There are lots of people who will spend $50 on a new heat sink in order to get a 3C drop. :-)

4) I'd like to see more details about your lapping method. How much lubrication did you use? Did you use a glass backing plate? What was the brand/quality of the sandpaper? How much Ceramique did you use when you reapplied your heat sink? Etc... These and more can be factors that would affect your end result. <edit - I saw where you used a mirror>

5) The return on investment is actually pretty reasonable. I don't know about everyone else, but I sell kits pretty cheap. If done right, even with the nine-sheet premium kit, it should only take about 1-1.5 hours to lap a large heat sink.


Please understand, this post isn't a flame, I'm just pointing out some points that are worthy of consideration. In fact, I'll put my money where my mouth is.... JMKE, PM me and I will send you a free premium kit to take a look at and try out. Fair enough?

BTW... I have sent a couple of premium kits to Madshrimps, one to use in a review and another to use as a giveaway. Should actually be appearing soon.

jmke

Hello Insulglass , welcome to our forums

1) the Zalman CNPS is pretty flat, but could indeed use a lapping, with 1200+ grid paper only though, since it has very few imperfections

2) I couldn't find any smaller grid then 1200 in local DIY hardware shops, 1200 is very fine already, and as you said, beyond 1200 performance increases will be neglilable;

3) It all depends on the original state of the material, if you have a badly lapped heatsink and your P4 IHS is very concave or convex then lapping, even with 600 grid, will give you a higher temp drop (2-5°C range).

4) this goes together with 3). I took pics and noted down data during the whole lapping progress and I'm working on a full "howto" article, including more P4 IHS and heatsinks to evaluate. here's the the info:
* used a mirror
* P600/P1200 silicon carbide waterproof , don't have the brandname lying around unfortunately, packaging has been thrown away
* how much Ceramique, dot in the center of IHS, makes the CPU looks like this afterwards (Another P4 & AS5 in pic)


I will send you a PM right away, thank you for the offer, we will evaluate the EasyPC kits fair and square. If they offer good performance increases over normal "grid's" and drop the CPU load temps considerable we'll make sure everybody knows it

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Sidney

Lapping heatsink does have more return of investment than simply replacing heatsink fan or just the IHS.

Due to manufacturing process in Mass, surface flatness is "always" questionable; hence Intel stock Hsf uses pad to "cushion" automated manufacturing process. Cutting, casting curling processes generate heat which cause the metal surface to "cure" or "settle" in different rate. Lapping an Intel Stock sink alone (both copper or alum) always yield a few Cs' reduction. With a few C's reduction from Intel Stock Sink, you are into the 3rd party high performance sink performance territory.

Based on my hobby in "sword and knife" over many years; a right job in lapping of two surfaces creates a so call "suction" effect that it seems to be super-glued together.

I only use glass block (8"x10") start with 400; 800; 1200 and finish with 1500 and a few drops of detergent and end with sewing machine oil.

My problem with lapping is; you'd almost have to re-do after each installation specially with "real" copper being soft the impression of the IHS is shown on the sink.

Improper lapping could ruin the sink.

Should try with NB and Graphic card sinks; you'd be surprise!!

Depends on how many give away --- we need a workshop in lapping before the LAN Party.

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lazyman

Opteron 165 (2) @2.85 1.42 vcore AMD Stock HSF + Chill Vent II

insulglass

Well, I don't mind sponsoring the odd contest or two. Good for the site, good for my business too.

I don't want to give TOO many away, though.

jmke

TerAngreal is using the EasyLapping kit on his P4 , after a few hours this is the result ->

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jmke

He will post temperature results very soon

here's a close-up:

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TerAngreal

this is what the victim looked like before i started the 2 hour lapping job

DUR0N

keep in mind that lapping does not help one bit if you don't straighten out the concave form.
It might look like a mirror, but that doesn't mean the surface is flat.