lapping my Ultra-120 Extreme cost me $90 (to replace it)

[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. $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 &#37. 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

I got a much larger drop after I did the IHS of my Q6600 as well. You can read about it in this thread. As always, there are before/after data and pics before, during and after.

Enjoy!

[Spawne32]

did you do a flatness test to ensure that its even? have you tried modifying the mounting system any to get it to make better contact if you took too much off?

[hotrodtheman]

Sorry to hear about that bro, and I know you don't really want to hear this but you saved alot of our asses. I said I was gonna lap mine, but I guess my first thoughts were right. Thermalrights products have the greatest quality and efficiency , I knew that they didn't just get lazy and screw up the base. The fact that its slightly convex is not surprising, I'm actually glad they made it that way, this has recently become very popular in watercooling.

I lapped my apogee waterblock which was convex, and now my idle/load temps are both 10c higher. It hurts when load @1.52 vcore was 48c and now its 58c

[graysky]

I haven't tested it beyond putting a drop of water on a pane of glass and then placing the heatsink on the water drop, it looks very uniformly distributed from the bottom, looking up -- much better than when I did the same test before I lapped it.

No, I'm finished modifying my PC for the moment. No way am I gonna f*ckup the MB now. I'll post some pics of the process.

[graysky]

Here are some pics of the process (they're all in one 1.2 meg file - sorry for your analog modem folks). Anyone tell me what I did wrong?

[hotrodtheman]

The only thing I can think of is it looks like you only sanded in 1 direction left to right, but I'm not sure if that actually has an effect. Other than that it looks good.

[Scyth3]

Is your CPU lapped? Maybe your cpu is alittle concave, making a convex thermalright a good fit.

[ZhaoYun]

Hand lapped? Lapped on a flat surface, like a mirror? Looks uneven.

[graysky]

@hotrodtheman: as I did it I went back and forth for about 1 min, then rotated 90 degrees, 1 min, rotate, etc. I think the pics are misleading.

@scyth3: No, it's not lapped and given my track record lapping it will never get lapped

@ zhaoyun: yeah hand lapped using a piece of glass on a flat counter top. I dunno why it looks uneven.

[Daveb2012]

Lapping is not a bad idea, you just did a poor job no offense. it shouldn't hurt temps if its perfectly flat. I lapped a Scythe Ninja and it improved temps by a few *. Also when I do the glass test one small droplet will evenly cover the hole bottom of the heat sink when smashed against the glass.

[graysky]

@daveb2012: no offense taken. What did I do that's so poor? I removed the nickel plating, exposed the copper, etc. What would you recommend after seeing my pics?

Thanks!

[lad]

graysky, I think it's far more likely that you don't have good coverage of TIM, or your mount is too loose.

Also, if you see retention bracket marks in the HS now, how could it not have touched the retention bracket before lapping?

C2D's are -famous- for being concave, which requires lots more TIM. Put a -thick- line of TIM on your cpu, pointing from one side of your case to the other (IE, up and down, if you have a tower case), and see what your temps are.

Also, to verify, this thing does -not- use plastic pushpins, right? -Everybody- mismounts pushpins, they take lots more pressure to mount than you'd think.

It's a shame you bought another one... see if you can return it without a restock fee, else ebay it. There's no reason you can't get great temps after lapping. At -worst- you'd make the heatsink convex, which should work -better- on a concave C2D.

[Daveb2012]

@daveb2012: no offense taken. What did I do that's so poor? I removed the nickel plating, exposed the copper, etc. What would you recommend after seeing my pics?

Thanks!

well heres the method I used that seemed to work for me.

1st I used the following grits:
# 400
# 600
# 800
# 1000
# 1200
# 1500

I then used glass from a small picture frame maybe 3x2". I wraped tightly the sand paper around the glass making sure it was perfectly flat. I had the heat sink up side down, bottom facing up, then applied even pressure pushing down on the bottom of the heat sink. I tried to use a small circle motion, I also used water with all the papers.

[Navig]

Interesting and a bit concerning. I'll probably go ahead and lap mine in the next few days. I know my e6600 prefers lapped sinks, because it dropped 4c off the load when I lapped my Tuniq.

[Spawne32]

chances are you probably applied too much pressure to one side and made it uneven, no worry tho, i did that with my XP-90 and i easily corrected it by relapping it some more. You can check for evenness by doing a grid test with a piece of grid paper, or using a razer blade to check for gaps under the blade itself.

[graysky]

graysky, I think it's far more likely that you don't have good coverage of TIM, or your mount is too loose.

Well, I think I have a good feel for the right amount of TIM to use do to about 8 trials before I lapped it. I did the experiment where I used more TIM than AS5 recommended and the temps were high.

Also, if you see retention bracket marks in the HS now, how could it not have touched the retention bracket before lapping?

It's probably that it did, but that the nickel plated stuff didn't show it.

Also, to verify, this thing does -not- use plastic pushpins, right? -Everybody- mismounts pushpins, they take lots more pressure to mount than you'd think.

It's a shame you bought another one... see if you can return it without a restock fee, else ebay it. There's no reason you can't get great temps after lapping. At -worst- you'd make the heatsink convex, which should work -better- on a concave C2D.

No, they're metal screws. I guess I could sand down the edges to make it convex again but how will I know if I get the slope right? Sounds like more trouble than it's worth.

[graysky]

chances are you probably applied too much pressure to one side and made it uneven, no worry tho, i did that with my XP-90 and i easily corrected it by relapping it some more. You can check for evenness by doing a grid test with a piece of grid paper, or using a razer blade to check for gaps under the blade itself.

No, it's flat. I colored all over the base with a black marker and lapped that w/ 800 grit paper, about 5 circles was all it took to totally remove the marker.

[Hachi_Roku]

didn't see you mention it before but is your ihs flat, concave (like most/mine), slanted? that's about the only thing aside from no/not enough tension from the bracket that i can think of. was going to lap mine when i got it but i might wait a bit now

[Omastar]

Long story short, I just ordered another Ultra-120 X to replace this one. My wallet is $90 lighter. Do yourself a favor: don't try to lap a heatsink.

Just because you screwed up lapping doesn't mean you should demonize it for others. It's a fairly exact science in terms of lapping on a completely level surface, and if you had fears of messing up, you shouldn't have attempted it.

[Speederlander]

With my enzo and QX6700, I lapped only the CPU, but not excessively. I found that my poor temps were coming from the heatsink base actually hitting the CPU/mobo lockdown frame. On my bad axe 2, I removed the frame and dropped my temps about 10 C. You just have to be careful not to over tighten.

[hotrodtheman]

I know you said you wouldn't lap your IHS, but when I lapped my concave IHS my load temps dropped 13c

[graysky]

Everything is good, see the first post of the thread which I edited. Thanks to all who replied.

[ineedaname]

If that's the case where u didn't apply enough as5 that would lead me to think that your CPU IHS is not flat at all which is why you would need more AS5.

When both surfaces are completely flat u don't need much as5 at all but if they're not flat then u need more as5 to fill in the convex or concave parts.

[james111]

Thats much better
I was planning on lapping mine anyways.

[Scyth3]

How come so many people said he screwed up on lapping? How can you tell if it is flat from his pics? You did a good job and you should lap your cpu too.