DLS2008 Posted July 29, 2008 Posted July 29, 2008 I'm building a new rig, but my dad decided to buy the parts without consulting me. He bought good parts, but he got a Zalman cooler. It would work fine for stock settings, but I want to overclock. I'm looking into possibly exchanging for a Thermalright Limited Edition Ultra-120 Extreme. I'm wondering if I should lap one or both of the heatsinks? I have double of everything for 2 new rigs and I'd probably only get one TRUE because of the money. I've heard some say that the TRUE is supposed to be convex and others disagree. So tell me whether I should lap one or both of the Zalman and TRUE. Also, should I lap the CPU itself? Finally, if you recommend lapping, where can I get my hands on some like 800+ grit sandpaper. The best I've seen is 800 grit in stores near me. I would like to go to at least 1500, 2000 if I can get it. Share this post Link to post Share on other sites More sharing options...
Nemo Posted July 29, 2008 Posted July 29, 2008 Here's an excerpt from a review at FrostyTech: The Thermalright Ultra 120 Extreme heatsink has a surface roughness of approximately 16 microinches, which is considered excellent. The nickel plated copper base of the Ultra-120 Extreme is machined smooth, but it's not entirely flat. The base is perfectly flat in the axis parallel with the heatpipes, and noticeably convex in the axis perpendicular to the heatpipes. You can see the curvature in the image below. A known straight edge was held to the base in front of uniform light source. As popular as the Thermalright Ultra-120 Extreme is, this curious base 'treatment' by the manufacturer has spawned a cottage industry amongst CPU heatsink retailers for pre-lapped heatsinks. CrazyPC.com offer a lapping option with purchase from their site for an extra $19. Source: Frostytech.com If you follow the link you can see a picture of the base. The best thing is to also get some responses from guys here that have the TRUE to see if they saw the same thing on their heatsinks. Share this post Link to post Share on other sites More sharing options...
Verran Posted July 29, 2008 Posted July 29, 2008 I lapped my TRUE and I can say it definitely wasn't flat. I didn't take pictures, but I think it's very much worth the effort and I've heard a lot of people here say the same. Thermalright has a history of not-flat bases all the way back to at least the XP-120 which a lot of people (including myself) lapped as well. As for lapping the cpu... it's easy enough and they're usually not flat either, but it's also a lot easier to mess up and a lot more expensive if you do. So that's a decision for you alone... Share this post Link to post Share on other sites More sharing options...
OwinC Posted July 29, 2008 Posted July 29, 2008 To be able to find out if it needs lapping use a razor or straight edge ruler. Napa or Auto Zone would have the 1000, 1500, 2000, 2500, 3000. But the finer grits would be used more for polishing rather than lapping. When I lapped my processor and heatsink. I used 320, 600, 800, and finished with 1500 grit paper. Do not forget to use a a nice size piece of glass. Possibly a mirror or the glass out of a picture frame. Share this post Link to post Share on other sites More sharing options...
Compxpert Posted July 29, 2008 Posted July 29, 2008 Never even bothered to check mine. My temps are at 60C full load at 4.2GHz. Share this post Link to post Share on other sites More sharing options...
hardnrg Posted July 29, 2008 Posted July 29, 2008 ending on 800 is fine... I did my TRU to 1500 and I think I did my XP-120 to 2000, I definitely did my Thermaltake Silent Boost to 2000+ as it really was a mirror finish, but it really doesn't make much difference at all over 800 in terms of thermal transfer as it is very flat and smooth by the time you get to 800... anything higher *looks* nicer though if you just did 400 followed by 800, it would be a lot better than stock, and probably perform within 1 Share this post Link to post Share on other sites More sharing options...
DLS2008 Posted July 29, 2008 Posted July 29, 2008 So from what all of you posted, I take it that it should actually be flat and not convex like it comes. Does anyone have any test results or at least temperature differences between lapped and not lapped so I can decide if it's worth my time? Is a progression of 320, 400, 600, 800, 1200, 1500, 2000 good? I know it's not necessary to go past 800, but I like the pretty mirror finish, lol. And one last thing, is it all wet sanding? Do you sand in circles or do you do one direction then rotate the HS and go the other direction, I've heard people say both ways, is there a difference? Share this post Link to post Share on other sites More sharing options...
dr_bowtie Posted July 29, 2008 Posted July 29, 2008 what Zalman did you get? if it's the 9700 I would just keep it as it's very on par... why spend the extra money on a Thermalright and then have to spend extra time to lap it flat... isnt this what you are paying a premium for... I just bought a XP-120 for my HTPC and had to spend a hour and a half lapping it cause it was one of the worst heatsinks for flatness...it was crowned inwards on both axis and the center wasnt even touching the heatsink at all...it was out a whole millimeter... I have bought dozens of Zalmans and all of them have been the flattest I have ever had....not to mention the XP-120 was 5c higher in temps with the exact same TIM application compare to the 9500 I took off it... I will NOT settle for a high price on a heatsink and then have to resort to making it flat in the process nomatter what the analogy is... if you have a 9500/9700 just run it and see....I have a 9700 on my Q6700 and I have had it to 3.8ghz and temps never went over 60c across all cores at 1.5v and thats on a Quad...dual core wouldnt put out as much heat...(only slightly less) there you have it... as for lapping...I rough cut with 320grit and finish it off with 400grit...with 400grit and very light pressure it does as good a job as 800grit... you really dont need a mirror finish on a heatsink to do the optimal job... quite a few I have found a 400grit job does as good or better than some mirror finished job... the important part is flatness... Share this post Link to post Share on other sites More sharing options...
PeterStoba Posted July 29, 2008 Posted July 29, 2008 I'd definately do it! Just don't do anything like this : http://www.tomshardware.co.uk/forum/253302...800gt-110c-idle Share this post Link to post Share on other sites More sharing options...
DLS2008 Posted July 29, 2008 Posted July 29, 2008 I'm not retarted! Now that we have that cleared up, I think I'll test my Zalman, then possibly lap that. If I still want lower temps, then I'll buy the TRUE and test that, then maybe lap the TRUE. Now if only I had a motherboard and some RAM, lol. Share this post Link to post Share on other sites More sharing options...
dr_bowtie Posted July 29, 2008 Posted July 29, 2008 As I said.... I havent had a Zalman yet that needed lapped...I have 8 of them here and have bought dozens... What I do is get a machinist straight edge that measures the flatness...you'll know right away if it's out or not... Share this post Link to post Share on other sites More sharing options...
mistabonz Posted July 29, 2008 Posted July 29, 2008 I will tell you this I upgrade to a 120 extreme and an antec 1200 case over this past weekend. I lapped the cooler and added a sythe fan at 133cfm and my temps went from 40 idle and 49 at load down to 27 idle and 36 under load so in my mind it is every bit worth the effort to lap the cooler. I am estatic with my temps so I will not be lapping my cpu. And to boot these temps are using Thermalrights chill 2 thermal compund. Have Arctic silver 5 but read some very positive reviews on the chill and decided to try it and I must say the reviews were right on. Share this post Link to post Share on other sites More sharing options...
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