Lapped my Ultra-120 eX (pics and results)

[graysky]

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. Plug: [url=http://forums.vr-zone.com/showthread.php?t=105586=SLi_Dog[/url] wrote a great guide for HS lapping.

$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.

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

[Cedars]

Lapping job looks nice... but was it really worth it ? Temp difference wasn't so spectacular.

Dr. T

[kent1146]

A 2C drop is pretty significant, when you consider that he didn't buy any new gear, or change any settings. He just put a little elbow grease in to make the stuff he currently has work better.

Some people think it's worth the time and effort, especially if he can get a slightly higher overclock out of it. Other people don't, because the 2C difference is insignificant and impractical to them. But then again, none of us became hardware enthusiasts that try to squeeze as much performance out of our hardware / wallets because it was practical

[graysky]

@Cedars - yeah, I only got 2 °C out of this, but when I lapped the CPU I knocked 7 °C off the coolest core and 10 °C off the warmest core. To me that's suggesting my IHS was pretty bad and you can see from the pics that it was pretty uneven.

@kent: Good point: didn't buy any new hardware. From a bang-for-the-buck analysis, lapping has to be one of the best mods.

[PriMaTe]

Nice work, 10c total is a nice drop for the price of sandpaper and a little time. Your write-ups are great.