I just heard about this technique on the ncix.com forums and wonder if any of you guys have done it, and is it worth doing?
Notice that the article is from 2002.
The gains from this are far less now than when the article was written. Processors now have much larger surface area for the contact point between the heatsink and the core (compare images below). Also the newer smaller technology and lower power consumption designs generate less heat.
Notice the (old) tiny contact point (left center) vs the (newer) full area contact surface.
None the less, getting your heat sinks surface to a mirror finish can cool your cpu 5-10 degrees C more than the typical sink the way it comes from the factory. I have seen it with my own eyes. I have pulled a heat sink that was running at 52 C, polished it and got 44 C afterwords and I didn't even go all the way to mirror. You can find some techniques online by googling "heatsink lapping" but basically you need a glass plate (like from a picture frame) wet/dry sand paper varying from 100 to 2000 grit (the grit in the 1000's is hard to find and expensive) and some time. The best I have done (52 C to 44 C) was done with a final grit of 600. The best technique I have found is to sand on the plate starting close to yourself and pushing away in a strait line then lifting come back towards yourself and start the next pass, I tried sanding in a circular motion but got less pretty results. You definately do not want to sand pushing away and again back towards yourself, the back and forth rocking can cause irregularities. If you can find a glass plate at least as large as the sandpaper you get, you can make the paper stick to the glass when its been wetted, and it will stay in place fairly well as you push the sink across the paper holding it flat and in the same position all the time. Not only will this give you a smoother surface but will take out and irregularities in the level of the surface of the sink. Most times I have done this the sink sands at the outer edges of the square sink first, leaving a round space in the middle of the sink untouched. The worse this effect is the more important it is to start with a coarser grit to attain the level before going for shine. In other words it can take 6 hours of sanding with 600 grit paper to clear the space in the center of an off level sink, but using 80 grit or 100 grit will clear the space in 10 or 20 min. and then going to 200 grit then 400 grit then 600 grit over the next hour will finish it off. 600 grit will not give you a mirror finish, you need the grit in the 1000's range for that, but I did see one tutorial where the guy suggested a final polishing with just plain paper to get the shine. I tried it but it seemed it would take too long to achieve anything worth the effort. I do want to try using a liquid polish (car polish maybe) on paper to see if I can get the effect of 2000 grit some what cheaper.
Last edited by Appzalien; 12-03-2006 at 05:41 AM.
automotive stores usually have sand paper with grits in the 1000's. you can also lap the heat spreader on the cpu or gpu but that requires alot of prep work for gpu's.
Sanding to the point of a mirror finish is a total waste of time.
The object of the exercise is to achieve a flat surface, not a shiny one.
Most quality heatsinks are already flatter than is easily achieved at home.
BTW, this procedure is NOT lapping.
Lapping refers to abrading the two mating surfaces together to achieve optimal surface contact. Thus, instead of sanding each piece on a glass-backed piece of sandpaper, you'd apply lapping compound (available in a variety of grits) directly to the CPU's IHS and rub it directly against the bottom of the heatsink.
This would result in a perfect match between the two surfaces, so perfect in fact that, taken to the extreme, it's possible to create a vacuum seal between the parts. You'd be hard pressed to separate them without destroying one of the parts.
If you are still determined to sand these parts, I'd suggest you start with the CPU- not the heatsink.
The IHS on today's chips is not especially well finished and would probably repond better to touch up work than a decent heatsink.
Early generation Conroes are notorious for having concave heatspreaders.
"I am the one who knocks."- Heisenberg
I finally got this thing and installed it, but being that its pretty huge and my case is TINY everything is hitting in like my HD and PSU. I cant even assemble my case back together cause the HD will be in the fan on the freezer. Im stumped on what to do.
E/ There actually is an alternate way of mounting a HD in this case which is to fasten it to the bottom of the case, the only bad thing about this is its causing a fair amount of case vibration, a lot more then it had being setup the other way. Now my question is, is there such thing as silicone washers or anything like that which I could put between the HD and the case to dub down the vibration?
Bring the screws to an auto parts store. They'll have plastic washers or rubber hosing that should work.
Alright, one other thing that id like to mention is ive noticed the base of this cooler doesn't over the the whole CPU diode. From reading review on it, they claim that its normal. Now should I be concerned about that?
E/ If you guys have any other ideas on how to silence my harddrive by all means shoot some ideas. The whole suspending it idea wont work because of where its mounted to. Here is a pic just to show you what im talking about
If not, simply laying the drive on a couple of these pads will do the trick.
You could use Velcro to make the drive even more secure should you find it necessary.
Be sure to enable SMART monitoring of your drive and keep an eye on the temps.
"I am the one who knocks."- Heisenberg