Lapped my ultra-120 extreme (pics and temp results) - Overclock.net

graysky · 05-12-07

When my Ultra-120 X and I have to say I'm a little puzzled. The base where it should contact the heat spreader is not smooth at all, it's actually grooved! You can see a scratch which is where I gently ran my thumb nail over the surface; I could feel the rough edges.

Have a look for yourself:

Anyway, others encouraged me to lap it which I've never done before. After wrestling with the idea for a couple of days as well as reading many articles/guides, I decided to give it a go. $20 worth of sandpaper, a $2 piece of flat glass, and 4 hours of careful work (and sweat) later, I was left with a pretty darn flat HS. You can see by the pictures that this particular one was quite concave instead of being flat which isn't good for keeping contact between the HS and IHS of the CPU.

Did it work you're probably wondering. The temp data as measured in speedfan.exe for a ~1 h x264 encode (uses all 4 cores with a CPU load of >99 %). I had speedfan log the temps (which it does every 3-4 seconds) and I averaged the whole data set per core for the 2nd pass of the 2-pass encode (the 2nd pass is the most CPU intensive). Room temp for both experiments was ~23 °C. By the way, I added a constant of 15 to each core in speedfan since it incorrectly displays temps for quads by 15 °C.

System specs: Q6600 @ 9x333=3.01 GHz (stock voltage), P5B-Deluxe in an Antec p182 case.

Code:

Before lapping the HS:

Core 0: 66.9
Core 1: 66.4
Core 2: 60.6
Core 3: 60.6

After lapping the HS:

Core 0: 64.9
Core 1: 64.4
Core 2: 59.0
Core 3: 59.4

Delta:

Core 0: 2.0
Core 1: 2.0
Core 2: 1.6
Core 3: 1.2

JoBlo69 · 05-12-07

sweet...

**grunion** · 05-12-07

Nice! Are these temps at stock voltage?

pbasil1 · 05-12-07

Very nice...

graysky · 05-12-07

Quote:

Originally Posted by grunion

Nice! Are these temps at stock voltage?

Speedfan measured the vcore @ 1.31v (full load - after vdroop) for these tests. I have since learned that I can drop it to 1.25v in speedfan under full load, again after the vdroop.

tr8rjohnk · 05-12-07

That's pretty cool but why stop at 800 grit? That's still pretty coarse paper.

graysky · 05-12-07

Quote:

Originally Posted by tr8rjohnk

That's pretty cool but why stop at 800 grit? That's still pretty coarse paper.

I actually finished off 1/ 1000 grit but as I understand it, anything beyond that is purely cosmetic... and since it'll be out of sight, I didn't care about how reflective it was

insulglass · 05-13-07

Quote:

Originally Posted by graysky

I actually finished off 1/ 1000 grit but as I understand it, anything beyond that is purely cosmetic... and since it'll be out of sight, I didn't care about how reflective it was

Good job... but if you're gonna go that far, you really should go beyond 800/1000 grit. No doubt, the improvement is mostly already accomplished but there are still gains to be made by going further.

Ask any race car driver if he's like to have just 10 MORE HP! even in a 500HP engine and the answer every time will be yes. :-)

David

imperium11 · 05-13-07

you should go to 3000 grit purely for bling purposes

great job either way

Martinm210 · 05-13-07

nice work and great photos!

Lapping is probably more important for the quad than C2D. Some of the water boys are actually bowing the base purposfully to be convex and gaining a few degrees C. Swiftech Apogee GTX CPU waterblock actually comes with a thicker o-ring to make it concave.

Those quads also put out some serious heat, looks like the extreme is doing a good job for you.

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Lapped my ultra-120 extreme (pics and temp results)

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