CPU and Heatsink Lapping Guides

Q6600 Heatspreader (IHS) Lapping

(For Thermalright Ultra 120 Extreme Lapping, see further down)

Well, after lapping my HS, I've had this nagging little voice in my head telling me to do the same from the CPU. I did the job with 800 grit sandpaper. Initially, I told myself I'd just buff what's there right now just to see if it's level. After about 30 laps in one direction and 30 in the other direction I discovered I had quite a concave IHS. So I just kept at it. Two 9x11 pieces of 800 grit later paper later I was left with a darn flat layer of copper looking back at me. I finished the job and put a mild shine on it with a sheet of 1000 grit I got from the local auto parts store just for the f*ck of it.

Here are a few pics and the temp. results I got from lapping both my CPU and HS. I would recommend that anyone wanting the best $20 decrease in temps should consider lapping both the CPU and HS.

Hardware details: Q6600 @ 9x333 and vcore of 1.2625V in the BIOS, P5B Deluxe (vdroop modded) cooled w/ an Ultra-120 Extreme (lapped) with Scythe/s-flex SFF21F 1600RPM fan, in a P182 case:

Temp results:

Each temp. point represents an average of data collected over approx. 1 h time period during the 2nd pass of a 2-pass x264 encode of a 720x480 DVD source using a high quality video profile. Data points were logged by Speedfan every 3-4 seconds over this time period. The average CPU usage was >99 % on all 4 cores throughout the experiments. Also room temp was between 20-22 °C.

This is my preferred setup: 8x10 piece of glass on a flat counter top. You can see I cut the sandpaper into a thin strip (about 2-3x the width of the CPU) and attached it to the glass with some tape. The glass is in turn tapped down to the counter top to keep everything immobilized. You'll want to moisten the sandpaper with some water, then blot it until you have no pools of water. Remember, if you get water into your chip you're sunk. Then simple hold the chip and gently move it front-to-back. I don't recommend doing circles since they tend to give uneven results. The copper color on the sandpaper is material I just removed from the IHS on the chip.

Remember, you're after a flat chip here so don't push down on it as you lap: let the weight of your hands do it without extra pressure and go slowly so you don't use uneven pressure. After about 30 laps front-to-back, I gently blotted off the chip with a moist paper towel to remove the metal particles I just sanded off, then rotated it 90 degrees and repeated 30 laps front-to-back. Then you'll want to clean off the sand paper (add more water, then blot it damp and repeat). I'd recommend changing the sand paper frequently since it's really doing the work for you. That's basically it. You can start with 400 grit or so and lap until you can't see variations in the surface of the chip (no silver color is often a good indication that you're flat), move up to 600 or 800, then finish off with 1000 or 1200. I did mine entirely with 800 and 1000, it just takes longer with finer grits. Remember, the key is FLAT, not shiny. I would recommend that you do NOT polish the chip with a metal polish since you'll leave behind a residue that will hurt your heat transfer.

You can test the flatness at any point during the lapping process by carefully placing a razor blade across the surface of he chip and looking at the area where the razor meets the chip. Now position your eye so that you're level with the chip and pointing at a light source (a lamp will do nicely). Do you see any light coming though? If so, keep at it. Another test you can do is to take a black sharpie marker and make about 9 dots in a 3x3 grid on the surface of the IHS. Lap about 5 times, rotate, and do 5 more. Now look at the dots... did they wear off evenly? If not, keep at it. You can also simply draw an "X" from corner to corner on the chip and do this as well. Again, you'll looking for even wear.

After about 5 minutes of lapping in each direction with 800 grit. You can see how the nickel plating has come off around the edges first which shows you just how concave this thing really was:

After more lapping most of the nickel plating has been removed expect in the really low areas (the camera flash fired so close to the chip makes all the scratches show up much more so than they do under normal light):

Switched to 1000 grit, here's the result:

Another angle shows the nice dull reflection, still very so slightly concave at the extreme edges, but good enough for me:

I would recommend that anyone wanting the best $20 decrease in temps should consider lapping both the CPU and HS.

Oh, I also thought I'd mention that before I lapped the chip, I had a pretty big difference in core temps when loading with prime95 or 2x orthos: up to 6 degrees C (sorry I don't have a screenshot of this). Lapping the chip REALLY evened-them-out as you can see from the coretemp numbers after the IHS and base of the heatsink were lapped (stressed using prime95 v25.3):

The table I showed above was not based on prime95 or orthos, it was based on x264.exe which is a video encoder. It is good at using all 4 cores, but not as efficient as prime95/orthos which explains the differences in temps from that table.

Thermalright Ultra 120 Extreme Lapping

When my Ultra-120 X and I have to say I'm a little puzzled. The base where it should contact the heat spreader is not smooth at all, it's actually grooved! You can see a scratch which is where I gently ran my thumb nail over the surface; I could feel the rough edges.

Have a look for yourself:

Anyway, others encouraged me to lap it which I've never done before. After wrestling with the idea for a couple of days as well as reading many articles/guides, I decided to give it a go. $20 worth of sandpaper, a $2 piece of flat glass, and 4 hours of careful work (and sweat) later, I was left with a pretty darn flat HS. You can see by the pictures that this particular one was quite concave instead of being flat which isn't good for keeping contact between the HS and IHS of the CPU.

After 800 grit with flashlight (Image won't display in the forum for some reason)

Did it work you're probably wondering. The temp data as measured in speedfan.exe for a ~1 h x264 encode (uses all 4 cores with a CPU load of >99 %). I had speedfan log the temps (which it does every 3-4 seconds) and I averaged the whole data set per core for the 2nd pass of the 2-pass encode (the 2nd pass is the most CPU intensive). Room temp for both experiments was ~23 °C. By the way, I added a constant of 15 to each core in speedfan since it incorrectly displays temps for quads by 15 °C.

System specs: Q6600 @ 9x333=3.01 GHz (stock voltage), P5B-Deluxe in an Antec p182 case.

Before lapping the HS:

Core 0: 66.9
Core 1: 66.4
Core 2: 60.6
Core 3: 60.6

After lapping the HS:

Core 0: 64.9
Core 1: 64.4
Core 2: 59.0
Core 3: 59.4

Delta:

Core 0: 2.0
Core 1: 2.0
Core 2: 1.6
Core 3: 1.2

Update by B-Unit:

A) A VERY flat surface to work upon. As mentioned, a countertop or solid (i.e. hard wood) desk.

B) A large enough pane of glass (8x10 picture frames are almost perfect)

C) High quality wet-or-dry sandpaper. [Note: For the early stages of my lap job, I used regular 110 and 220 wood sandpaper, which stood up to water amazingly well. However, for the finer grains (600 and up) you will want automotive sandpaper.]

Dont think that lapping is for the faint of heart. If your going to do this, plan on spending a weekend (at least) doing it. Dont bother if you only want to lap either your CPU or heatsink. If you dont do both, you will see almost NO gains in temperature. Also beware that lapping your CPU is inherently risky. So long as your careful to keep yourself grounded, you shouldnt have problems, but keep in mind that you are both generating huge ammounts of friction and placing your CPU near water, both generally not recommended.

Do you think they'd be better in two separate posts? That should fix the problem with the last image.

Hate to be this guy, but the order of your HSF pics HAS to be FUBAR. Pic 3 has the best reflection...

EDIT: O didnt bother to read follow up posts. Combined multiple threads I take it.

Extra EDIT: WTF?!?! You let a recomendation to use dish soap make it into the lapping guide. Your really blowing this moderator thing Randomizer...

Assuming this wont get deleted, dish soap just adds another substance which will potentially cause your thermal conductivity to be diminished. Straight water is more than sufficiant. The important parts are...

A) A VERY flat surface to work upon. As mentioned, a countertop or solid (i.e. hard wood) desk.

B) A large enough pane of glass (8x10 picture frames are almost perfect)

C) High quality wet-or-dry sandpaper. [Note: For the early stages of my lap job, I used regular 110 and 220 wood sandpaper, which stood up to water amazingly well. However, for the finer grains (600 and up) you will want automotive sandpaper.]

D) NO SOAP!!!!!!!!!!!!!!! If you dont believe me, Google it. I had planned on using soap until I decided one source was insufficient for a project of this magnitude.

Dont think that lapping is for the faint of heart. If your going to do this, plan on spending a weekend (at least) doing it. Dont bother if you only want to lap either your CPU or heatsink. If you dont do both, you will see almost NO gains in temperature. Also beware that lapping your CPU is inherently risky. So long as your careful to keep yourself grounded, you shouldnt have problems, but keep in mind that you are both generating huge ammounts of friction and placing your CPU near water, both generally not recommended.

Hehehheh, already did. Feel free to append my post to the end of the OP. You can even remove credit so long as the info makes it in.

Sry to be a prick about it, its your 'random' nature about these things that angers me so quick.

Ask for volunteers, I know there are regulars hanging arround who know these things.

Actually you could use soap (btw, I use shaving cream) for lapping insted of water, BUT you MUST clean it with distilled water and then 100% alcohol after if using soap,etc.

See below for pics of my lapping:
http://www.flickr.com/photos/24351647@N07/page3/
I have lapped the CPU about a week earlier and don't have much pics for it, but there is one : http://www.flickr.com/photos/24351647@N07/2393164766/
I only went up to 600 grit and I was able to get 3C cooler after lapping both CPU and HSF. There is no point going above that as the temp's won't change much, it'll only change about 0.2C. Also there was a thread over at xtremesystems or ocforum where they found out any thing above 800 is negligible performance gain and in some rare cases it could actually decrease performance as the thermal paste won't work effectively.

this lapping seams interesting. now i see this is about the cpu and the heatsink. will this work for water cooling blocks?

would it be worth my time to lap the hs that comes with the phenom 2?

To each his own but personally I've been lapping heatsinks and such as that for a long time, basically the same as listed as far as flat surface and such as that but I completely dry lapp, no water, definitely no soap of any kind.

Dry lapping is faster and you do not need any finer than 600 grit quality auto body paper to acquire a mirror finish and heres how to do it.

Set your paper on the flat surface and have a vacuum cleaner on hand, I prefer circular motion to attain my lapps and the most important thing is keeping the contacting surface completely flat at all times.

If you have deep scratches you may have to go as low as a 220Grit but if you do then 320, 400, finally settling in on the 600grit, for superior cutting when the particulates start to build up, use the vacuum with a brush attachment to remove the buildup, then go back at it.

Heres the mirror finish part, once your scratches are cut out stop vacuuming the residue and allow the residue to build on the paper, you'll effectively create a metal on metal polishing effect from the buildup, continue until you achieve your desired mirror finish.

This is the end result of lapping my AMD FX57, using the method I just described.

And this is the end result of lapping my Xiggy, again same method.

I did not post this to discount anyone elses method of lapping, there are so many different ways and guides out there.

I accidentally discovered this method when lapping a heatsink during a time the stores were closed, I was short of materials, and 600 grit auto body paper was the finest sandpaper I had at the time.

The more I continued the lapping process with the residue building on the paper, I began noticing the polishing effect beginning to happen, so I continued to a mirror finish.

I was amazed at the end results, and since then, it has been my adopted way of lapping period, with some amazing results.

Believe what you want, but try it for yourself, you'll get exactly the same results!

I hope this helps all of you! Ryan

Note: Don't rush your lapping job guys, thats the best advice anyone can give you, and do not use any coarser sandpaper than you have to, for the deep scratches you may encounter on some of these heatsinks, or you may create deeper scratches than you would have had to work out in the first place.

Also with an HDC [Heatpipe Direct Contact] style heatsink keep in mind the copper heatpipes outer walls are only so thick, so don't go Gorilla on that type heatsink.

Additional Note: Heres the hardest to lapp heatsink I ever put my hands to, lapping the Zalman was like dragging an Elephant around on a skinny what not table, its so top heavy.

But why lap the Zalman it had a mirror finish?

I cut out the stepdown so it would completely cover the AMD heat spreader.

Thats nice!

I lapped my Q6600 and im running it now at 3.2 ghz and my temps are at a max of 58. I lapped it mostly the same way, but i used a small block of foam that was used to protect my graphics card in its box, the foam is about 3/4 of an inch thick. that worked really well, it was very even. im using a thermaltake big typhoon, that was hard as hell to lap! its just too top heavy.

What was the foam for? LGA protector or surface for sand paper? Bad idea for surface good idea for protection.

AHHHH good then!!!

Oh my... I gotta lap my Pentium D now!

Think I got some silicon based 3000 grit sandpaper aorund here...
How long do you think it will take me?

Ok that makes sense

I still run one Pentium D its my daughters PC ...... she watches movies thats all! ROCK SOLID MACHINE!!! It will game withe 4850 that is in it pretty well!

Some notes on applying thermal paste to the Xigmatek
Imo, with DHT coolers becoming more prominent we should sticky that thread.

wow

I'm hot and cold.
QX9650 Extream 31-C h2/0_______gaming 34-C
Evga9800GX2 SSC 63-C fans______gaming 69/72-C

Zeemee1,

Very good post. You are looking for a FLAT surface - not necessarily a perfectly smooth surface. Microscopic scratches help to hold more paste.

What method do you use to check for flatness? What is the finest grit you use ?

Thanx