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lapped my IHS on a Q6600 (pics and results)

Discussion in 'Overclocking & Cooling' started by graysky, Jun 11, 2007.

  1. graysky

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    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:
    [​IMG]
    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 mildly soapy water (like 1 drop of dish soap in 1 liter of 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.

    [​IMG]

    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:
    [​IMG]

    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):
    [​IMG]

    Switched to 1000 grit, here's the result:
    [​IMG]

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

    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):

    [​IMG]

    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.
     
    Last edited: Aug 6, 2007
  2. freaksavior

    freaksavior To infinity ... and beyond!

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    very nice info, love the way you put it together

    but, might i suffest you do it oncemore but use 2000 and it will be the most shiny peice of metal in your house ;)

    how long did it take you?
     
    Crunching for Team TPU
  3. d44ve New Member

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    That is still scary with that many scratches still in it
     
  4. graysky

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    @freaksavior - Actually took about 2 hours totally, but I kept getting interrupted.
    @d44ve - I think the main thing is flatness and not such much fine scratches... the AS5 will fit them.
     
  5. graysky

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    I just edited/updated the first post of the thread with a few more pics and a brief description of how I lapped the chip for anyone interested.
     
  6. kenjin New Member

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    lol i see you posting this every where, saw the same post on toms hardware guide forum and pcper.com

    but good job on lapping it awesome result. i dont mind do my HS but i dont got the guts to do my CPU
     
  7. graysky

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    Sure you do dude.. it's actually much easier than the HS. Once you start doing it, you'll have no problem finishing it. I was the same way you were before I just took the plunge and did it.
     
  8. Mussels

    Mussels Moderprator Staff Member

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    i'm gunna have to go find me some sandpaper today... local stores only sell 800 grit at best, i want upto 2000 for this stuff :D
     
  9. Chewy

    Chewy New Member

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    go to an automotive shop or body shop. I found 1200grit at a hardware store but that was thier highest..
     
  10. Beertintedgoggles

    Beertintedgoggles

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    The AutoZone down the street from me carries up to 2000 grit, but if you can stand the wait it's loads cheaper to buy online. The only problem with lapping is once you start, you can't stop. I've lapped my cpu, chipset, gpu heatsinks on my current rig. I've lapped old gup heatsinks and chopped them up to cool my old A7N8X-E Deluxe MB. My old SI-97 is lapped in my gf's computer. My bro's and parents' cpu heatsinks are lapped due to me. Hell, I've even lapped the reverse side of an old 100 Mexican peso (have no idea where it came from... besides Mexico). I like my metal to be flat and shiny.
     
    Last edited: Aug 23, 2007
  11. Mussels

    Mussels Moderprator Staff Member

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    Heres a question Graysky, since you already did this -

    How many sheets of sandpaper did you go through, in the varying sizes?

    EG, one sheet of 400, then one of 800, then two of 1200, etc - just curious as to the amounts i should buy (i'm going to do a 775 CPU and heatsink, so your usage should match mine)
     
  12. lemonadesoda

    lemonadesoda

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    At all lappers:

    1./ Thin oil, or

    2./ water+soap ?
     
  13. FOXCONN1115 New Member

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    nice work, and a huge drop in temps, although still high for my liking :(
     
  14. Tatty_One

    Tatty_One Senior Moderator Staff Member

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    Damn, this has even got me think about taking the plunge! This might be a job for the weekend if I can get some ultra fine paper, if not I will superglue a handful of salt to some cardboard and try that.
     
  15. FOXCONN1115 New Member

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    LMAO :roll:
     
  16. Tatty_One

    Tatty_One Senior Moderator Staff Member

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    :D
     
  17. mas0n New Member

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    I found a small woodworking shop in Dallas today that sells every increment from 40 to 12,000 grit in single sheets :rockout:
     
  18. graysky

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    Anything over 1000 is a waste of $$$
     
  19. Mussels

    Mussels Moderprator Staff Member

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    i so hate you right now

    1200 and 2000 are good if you really want a fine polish, it depends the level you're at. I have 1200 for my best, and its still not 'mirror smooth' for those fanatics amongst us.
     
  20. Tatty_One

    Tatty_One Senior Moderator Staff Member

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    Managed to find a 5 sheet pack of 1200.....£2.79....that will do for me, a nice job for the weekend when I install my new CPU and PSU :toast: Although I am only doing the heatsink as I will probably be selling my new 6850 at Christmas so aint gonna do that....it would scare most flea bayers off!
     
  21. InnocentCriminal

    InnocentCriminal Resident Grammar Amender

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    Arrrh good stuff Graysky! Something I didn't give much thought, but I'll 'ave ago once I'm ready to WC my stuff!
     
  22. tigger

    tigger I'm the only one

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    i did this to my 6300 ages ago,a word of warning tho',this does void the warranty.
     
  23. nflesher87

    nflesher87 Staff

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    come to think of it, he probably SHOULD have mentioned that in the first post, as it's common knowledge to many of us, yet some still may have no idea...
    along with voiding the warranty, lapping can greatly decrease resale value so be careful there as well if you like to sell your old parts to get credit towards new ones!

    also in response to people's comments about wasting money and what not on certain grit sandpaper, I'm not too sure what you're talking about as my local auto store sells up to 2000 grit but at all the same price, all 3M sandpaper and I believe it was $.6# a sheet...which is definitely affordable to me, they were almost 8.5 by 11 size but not quite
     
  24. Tatty_One

    Tatty_One Senior Moderator Staff Member

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    Yup, thats why I am just doing my heatsink.
     
  25. average..

    average.. New Member

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    i would give it a go if it did not take me the best part of an hour to attach my freezer64 pro. im not going thru that again, lol
    i was certain i cracked the cpu die, the mother bored disconnected some capcitors.. the shock of my life when it actually powerd up.. maybe i will do my gpu's heatsink thats just a couple push clips.. oh and my MB's heat sink... will make a lapper out of me yet.. ;-)
     

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