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I saw some people and 'How to' lap your CPU or heatsink with sand paper. What does it do anyways? It makes it easy to contact thermal compound? And cools better?
 

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<div>Originally Posted by <strong>FearSC549</strong></div>
<div style="font-style:italic;">I saw some people and 'How to' lap your CPU or heatsink with sand paper. What does it do anyways? It makes it easy to contact thermal compound? And cools better?</div>
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It makes the heatsink and cpu flatter, which results in more contact area (as opposed to the various imperfect holes left by imperfect IHS and stock heatsinks). With added AS5, the temps drop as much as 15c idle and possibly 12c load (but don't quote me on it).
 

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Not 15c, not even close. Maybe 4 or 5.
 

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<div>Originally Posted by <strong>Retrospekt</strong></div>
<div style="font-style:italic;">Not 15c, not even close. Maybe 4 or 5.</div>
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My load temps dropped 10 c while running dual prime and idle 38-25c.
 

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At the microscopic level your IHS (Internal Heat Spreader) and the footprint of your HS (Heat Sink) look like a series of mountains and valleys. These gaps cause the heat transfer process to degrade.<br><br>
Smoothing the surface of matter allows for greater physical contact and therefore more efficient heat transfer. One indicator as to how "smooth" a surface is will be it's reflective properties.<br><br>
My temp drop averages around 8C... That makes me happy inside!
 

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<div>Originally Posted by <strong>Retrospekt</strong></div>
<div style="font-style:italic;">Not 15c, not even close. Maybe 4 or 5.</div>
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It depends, I've lapped quite a few cpu's and hs's now, and it can vary. It depends how flat they are to begin with, and <b>where</b> the imperfections are. I've had a couple cpu's (and hs's) that were concave or otherwise not flat, some are worse than others. Unfortunately cpu's seem to have a tendency to be concave, so the most important part (the center) is sunken down and not making very good contact.<br><br>
I've had lapping drop me only a couple or few degrees, sometimes 6-8 or a bit more even, so far it's <b>always</b> helped some. The more un-flat your surfaces are, the more it should help. Flatness is <b>way</b> more important than to be shiney and polished. If you by chance had a perfectly flat cpu and hs, then lapping probably wouldn't help much. But so far, I have <b>yet</b> to see a cpu or hs, which was perfectly flat.<br><br>
Once I start the sanding and use the sharpie trick, I can <b>always</b> see imperfection of the flatness, on cpu and hs surfaces. I did have one Big Typhoon (out of 4 I've purchased for me and others) that was dam close to flat. But then I had another BT that had a really uneven surface, it varies. Same for cpu's, my p4 prescott was ultra concave, others have been less uneven. Most important is to lap <b>correctly</b>, if you don't do it right and with care, and you're not <b>really</b> getting it flat, then you have nothing.
 

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Most heat spreaders are concaved, so lapping them gives a flat surface for more contact, also it removes the microscoptic imperfectsions on the surface of both the heat spreader anfd heat sink. on an average you get 3c to 5c temp drop.
 

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Two flat objects compared to two concaved objects touching...<br><br>
imagine that...there is like..a big sandwich of AS5 in the middle of the two concaves....<br><br>
When I lapped my BT, I got a 12C drop in load.<br><br>
That's without an IHS! I had the IHS off before AND after...so I must say....the combination of the two would have made quite an improvement had I dont them both at once....<br><br>
I'll never put on a heatsink again before lapping it.
 

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What is an IHS? Does it come with stock AMD cpu coolers? And how do you lap your cpu, sounds fun.<br><br>
Edit: And is AS5 worth it? I know its not a lot of money so what the hell <img alt="" class="inlineimg" src="/images/smilies/tongue.gif" style="border:0px solid;" title="Stick Out Tongue"> But does it reduce temps a lot? What % if it does?
 

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<div>Originally Posted by <strong>OCZedd</strong></div>
<div style="font-style:italic;">What is an IHS? Does it come with stock AMD cpu coolers? And how do you lap your cpu, sounds fun.<br><br>
Edit: And is AS5 worth it? I know its not a lot of money so what the hell <img alt="" class="inlineimg" src="/images/smilies/tongue.gif" style="border:0px solid;" title="Stick Out Tongue"> But does it reduce temps a lot? What % if it does?</div>
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IHS = Internal Heat Spreader<br><br>
Lapping: <a href="http://www.overclock.net/intel-air-cooling/119979-noctua-e6400-lapping-minor-case-mod.html?highlight=E6400+lapping" target="_blank">http://www.overclock.net/intel-air-c...=E6400+lapping</a><br><br>
Fun?... Afterwards, yes! During... for me nerve wracking <img alt="" class="inlineimg" src="/images/smilies/eek.gif" style="border:0px solid;" title="EEK!"> (New E6400)
 

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<div>Originally Posted by <strong>Syrillian</strong></div>
<div style="font-style:italic;">IHS = Internal Heat Spreader<br><br>
Lapping: <a href="http://www.overclock.net/intel-air-cooling/119979-noctua-e6400-lapping-minor-case-mod.html?highlight=E6400+lapping" target="_blank">http://www.overclock.net/intel-air-c...=E6400+lapping</a><br><br>
Fun?... Afterwards, yes! During... for me nerve wracking <img alt="" class="inlineimg" src="/images/smilies/eek.gif" style="border:0px solid;" title="EEK!"> (New E6400)</div>
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IHS is easier just to take off (if it's not epoxied)<br><br>
Lapping..well...lapping my BT for about an hour and a half...on the floor...my back hurt from bending over for a week...*****. But defn worth it for a 12C drop in load, and 100Mhz extra overclock.
 

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<div>Originally Posted by <strong>Sideburns</strong></div>
<div style="font-style:italic;">IHS is easier just to take off (if it's not epoxied)<br><br>
Lapping..well...lapping my BT for about an hour and a half...on the floor...my back hurt from bending over for a week...*****. But defn worth it for a 12C drop in load, and 100Mhz extra overclock.</div>
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Got any good links (I've seen some, but I would like a second and informed opinion) for removing the IHS on a x2 3800 and E6400? I heard horror stories of soldered diodes, is that true as far as you know?
 

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<table border="0" cellpadding="6" cellspacing="0" width="99%"><tr><td class="alt2" style="border:1px inset;">
<div>Originally Posted by <strong>Sideburns</strong></div>
<div style="font-style:italic;">IHS is easier just to take off (if it's not epoxied)<br><br>
Lapping..well...lapping my BT for about an hour and a half...on the floor...my back hurt from bending over for a week...*****. But defn worth it for a 12C drop in load, and 100Mhz extra overclock.</div>
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I don't think taking the IHS off is such an easy task on a allendale/conroe. I heard some people tried on conroe (and pentium D's I think too) and destroyed the cpu. I haven't looked into it much, but I haven't seen anyone who successfully took off the IHS on a conroe yet. I think something is actually soldered or epoxied like you said, and so it's very hard to do I guess.<br><br>
And ya, it's takes some time to do lapping correctly, but totally worth it you're right! I do it to all my cpu's and hs's. I voided the warranty on my e6400 10min after I knew it was working. Tore it back out, and started sanding away on it and the BT. <img alt="" class="inlineimg" src="/images/smilies/smile.gif" style="border:0px solid;" title="Smile"> Then sold it to a friend, got another e6400 that OC's a little better, and lapped it too. Then I did my e6600 and it's BT a few days later. It helped my temps some, but my last couple BT's haven't been too bad for flatness. Actually both the allendales and the conroe, haven't had too bad of surfaces either, not perfect though. I did drop a few degrees though for sure.
 

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Discussion Starter #16
Also, if I lap my CPU, does it voids the warrenty?
 

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Yes, very much so. lol....but by the looks of your CPU it might be up already?
 

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Discussion Starter #18
Oh yeah...i forgot, it expired...crap...So should i lap it? And is IHS removal and lapping the same??? I saw a video tutorial by Crash about removing the IHS, so, should i remove IHS or lap it? And which one works better?
 

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Find out if your IHS is soldered or epoxied first.<br><br>
IMO, I would remove the IHS (since your CPU is not new). You will get superior thermal transfer by eliminating the middle element that the heat has to travel accross.<br><br>
Be careful!
 

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Northwoods weren't soldered as far as I know. But just to be safe, lap it and see if you are satisfied and in the mean time, figure out if your chip has the IHS soldered on, and then if not, pop it off.
 
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