Currently lapping my Q9450

[Dangerer]

It's been over a year since I've had this chip and it's out of warranty anyway since it was OEM. I started out using 320 grit wet/dry and after a large sheet and about 3 hours, I couldn't get any further results so I switched down to 220 grit and I've been sanding for an hour and a half and currently this is my result.

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I marked the entire CPU with permanent marker prior to sanding and though all the permanent marker was sanded off, the nickel seems to still be present in the mid section of the cpu. I'm not applying any force at all but I can't get the mid section copper to appear. Also the edges are still covered with nickel as well and with the way the edges curve, I suspect I have a long way to go even with 220 grit.

is this normal at all? I read other reports of people sanding away the entire IHS in 6 hours and I'm closing in on that mark

edit: well I ended up spending an additional 5 hours sanding down the IHS while watching TV and browsing on my laptop to get down to pure copper at all edges. After that I spent an additional 3 hours lapping my HDT-S1283 making it perfectly flat and getting rid of the corner dents about .5mm thick from over tightening it from before.

For all the work that went into it, there was absolutely no change in my idle temps. At 27.5 ambient, my idle temps never went below 40c before and still can't now. I did about 30 minutes of prime95 small fft and my temps were maybe 2-3C lower if I remember correctly. If anyone is curious, I used MX-2 compound and applied it by filling in the gaps of the s1283 and then two lines along the aluminum base. sigh..

 

[Nickel020]

Well you do need to apply some force, othewise almost no material will come off. Without applying any force it's like polishing the nickel away.

 

[CurseTheSky]

I've read numerous reviews that said only use the force of the CPU itself to do the sanding, and make sure you keep it on a level surface. That'll probably give best results, but it may not hurt to apply a little bit of force to get rid of the nickel, then continue as usual for a while with higher grip paper to smooth everything out.

 

[BonzaiDuck]

I'm a bit surprised that you've done that much work and haven't reached the copper layer yet.

The nickel layer is pretty thin. Even so, when I first began my experience with "lapping," I didn't consider the thermal conductivity of the nickel layer, and I had made the IHS flat after a couple hours -- but it still was covered in nickel.

As for "applying force." I use the black-plastic CPU cap to cover the LGA when I lap; it has small tabs on the edges that grab the PCB of the CPU. Never thought about "how much force" I apply, but simply try to keep the CPU moving -- in circles, from side to side, front to back.

220-grit is the way to go when you get started, until you see that the nickel is only present on the outskirts of the processor cap. Personally, finishing with a 320-grit sandpaper is also fine, if you use it enough so that the sandpaper becomes degraded in the process -- enough to lose its grit so that it gives a polish that is more like 400-grit.

EDIT: I"m rather comfortable insisting that lapping down to copper really reduces temperatures -- by between 5 and 10C for a 65W core if both heatsink base and IHS are plated with nickel and lapped equally to bare copper -- by up to 5C if one surface is lapped to removed the nickel. I measured the difference carefully in 2007, and saw the improvement again when lapping some E21x0 dual-cores a year later.

I prefer nano-diamond paste like IC Diamond; will never use anything else. It costs more, but then, I'm also confident about controlled measurements taken with nano-diamond as opposed to AS5 in 2007 -- with, and without lapping.

 

[VirtualLarry]

Why spend all that time lapping, when you could just spend more $ for a better cooler?
Just for fun?

 

[faxon]

well it's cheaper to lap it than buy a better cooler in some situations, and what about if you are on high end water to begin with. a serious upgrade to your loop would be a chiller costing several hundred bucks, where as lapping it might net you another 5c for like $20, with some of the cost being recirculated every time you lap osmething else, making it worth more in the long run