HSF lapping success!!!

gamerman4

Active Member
As some of you know, I had a previous thread that said I had a heat problem. I decided to lap my SI-120 at first but as I researched lapping, I figured I should also lap the silver IHS on my A64!! Great success!! My previous idle temp was around 36-38C....down to 33C!!! Previously, when running Prime for even 10 seconds my temp jumped to 55-56C....down to 50-51C. In about a week, I will get some Arctic Silver 5 :D and I will post back at my temps then. Also some neat info I learned while lapping them. The SI-120 (XP-120) has a thin aluminum layer right below some copper. I lapped the aluminum all the way off and now have a mirror-like copper finish on my SI-120. Also, the IHS on the A64 is also copper with a this coating of aluminum. I sanded it down flat but with only 800 girt and 1000 grit sandpaper, I couldn't get the entire thing copper. I was VERY tempted to strip the IHS off and have a naked A64 3200 but I didn't feel like risking replacing it... After getting my AS5, I will even lap some more for added cooling and finally OC it even more!!. I will post back after getting my AS5.

This is the lapping guide I used:
http://www.overclockersclub.com/guides/heatsinklappingguide.php
 
I still don't get lapping, My HS is very smooth already[smoother then 12,000 grit sandpaper[BY TOUCH], which is yes soother then reguler paper, because itryed sanding paper and it got smoother :) ] and is in mirrow like already.

And Yes there are microscopic scraches that you cant feel, but thats what thermal compound IS FOR.
 
Thermal compound fills in the cracks for better thermal transfer but contact between HSF and CPU is better than CPU to TIM to HSF contact. The less cracks there are for your TIM to fill, the better pure contact between heatsink and CPU which is what you need. If you could somehow make it so CPU and heatsink were PERFECTlY flat with not even a miscroscopic scratch in it, Thermal compound wouldn't be needed but it is here to compensate for machine error becasue it is virtually impossible for an infinitely and perfectly flat surface. Also, most heatsink are flat to the touch because there are TINY height variations as small as .0001" which can make a huge difference when contacting your CPU. You can not detect height variations that small my touch and rarely just by looking but if you were to take a marker and draw over the surface of the heatsink and lap it for about 10 minutes, you would be able to see that part of the marks will be sanded off while some of it will stay on because of the height variation, the sanding couldn't get to that part of the mark. This was evident with my heatsink because there were two splotches of copper where the height was tallest while the aluminum was still covering most of it, after about 1 hour of lapping, most of the copper was showing through but there still was some aluminum which indicated dips in the metal.
 
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Still, mine seems scrachless and mirrorey already, :? idk...maybe i'll try it and see any difference...I already have the sand paper, and alot finer too.
 
where do you get 12,000 grit sandpaper? anyways, if you look at the IHS of an A64 CPU, there is no reflectiveness to it AT ALL. This is because they dont machine IHSs flat, its concave. After about 30 mins of lapping the IHS, I could see myself in the IHS :D.


Note: for anyone who doesn't know. an IHS is the metal covering of most newer CPUs like newer P4s and AMD 64 CPUs
 
Auto parts store, for sanding scraches out of your car,and a long time ago i got some off ebay for buffing out acrilic scratchs.
 
smoother then 12,000 grit sandpaper[BY TOUCH],
1. Sandpaper isnt supposed to be smooth.
2. You got a link for 12K grit paper???

And Yes there are microscopic scraches that you cant feel, but thats what thermal compound IS FOR.
And the less thermalpaste you use the better. So we can infer the less microscopin scratches the better
 
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