CPU & Heatsink Lapping - Are concave, convex, or flat heatsinks best for cooling?
Linus Tech Tips
·Linus Tech Tips
·2017-05-06
·
1,579 words · ~7 min read
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CPU and heat sink lapping that is a topic that I wanted to make a workshop
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video on and actually spent many hours attempting to do just that what the heck
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is it well theoretically your heat sink has teeny tiny little grooves and nooks
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and edges on the surface imperfections that will theoretically cause issue but
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even worse than this there are the curves convex concave or even the
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sought-after lack thereof also known simply as flat these are are all but
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variables in the overall equation of cooling performance within your system
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and some matter more than others the theory behind lapping is to neutralize
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said variables to remove the Curves and Imperfections and create something flat
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shiny and
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smooth Intel skull Canyon nuck features a sixth generation core I processor and
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Thunderbolt 3 learn more in the link in the video description down below to
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better explain how it is done I will explain the process from the start and
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we can use some of the seemingly endless footage of myself doing so in order to
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represent this You Begin by gathering materials you need a strong sturdy table
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that won't move shake or bend when things are placed on it the table
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surface would hopefully be glass but if not you should Source some relatively
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thick and heavy glass or a mirror as glass and a especially mirrors are very
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flat once you've sourced the flattest surface you can it's time to stop by an
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auto parts shop you need sandpaper and a lot of different grits of it I get wet
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and dry sandpaper and I would recommend you use a fairly standard progression of
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grits consisting of 400 600 800 1,000
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1500 and 2,000 wet the Sandpaper
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starting at your lowest grit and leave some standing water on it in order for
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the heat sink to Glide nicely tape the Sandpaper down to your surface and get
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to work keep note of the direction the heat sink is facing and slide it up and
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down the paper five times totaling 10 total passes when doing this control the
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tilt of the heat sink so that it is able to travel without skipping or tipping as
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it goes along but don't push down let the weight of the heat sink press into
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the Sandpaper instead once you have completed one round of this rotate the
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heat sink 90° once you've completed 10
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full rotations it's time to move up a grit as you can probably guess it's an
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extremely tedious process I would highly
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recommend putting on an audio book or watching a movie or something during the
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process just make sure you don't lose count there was tons of evidence online
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of this working really well for people albeit most of those were super old
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posts but either way it was fairly consistent for people to achieve
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anywhere between 1 and 5° of improvement
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in cooling performance after are lapping awesome perfect candidate for a workshop
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video that might actually have a conclusion that isn't you know actually
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it doesn't matter what you do because trust me it's not just you that's
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getting tired of that I want things to matter I hate it when things are just
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whatever Cable Management whatever fan placement whatever thermal paste
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application whatever I'm tired of it too
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so I grabbed a hyper 212 Evo thinking that it would be a good candidate
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because of how many freaking people own them if there's one small Improvement
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here it would have the biggest impact on the community due to just how many hyper
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212 evos there are there's a lot of them I then spent 3 hours sliding a heat sink
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back and forth the base of which had quite noticeable imperfections when I
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started and looked you know super nice and shiny when all was said and done
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before lapping it was able to cool a 4790k overvolted to 1.35 volts to 60 7°
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C in an ambient room temperature of 19°
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after lapping it cooled the same CPU with the same fan speed to 70° CS but
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the ambient temperature of 22° meaning
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that the temperature of the room went up 3° and the temperature of the computer
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or more specifically the CPU went up 3°
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also known as not a damn thing changed I was frustrated as I am now I felt like
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the results were off like I probably did something wrong I needed to do do some
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research and I did and armed with my recent results I found many additional
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sources of information many disagreeing with each other which is always
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frustrating when trying to get to the bottom of something when you're researching anything having people
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disagree with each other is kind of annoying the most thoroughly tested
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documented and investigated resource I could personally find was from Silent PC
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review namely the article 1366 also
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known as the post-title ourl CPU heat sync test platform here's where it was
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reinforced that the surface scratches and Imperfections are less of a big deal
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than the curve here's where it was reinforced that the curve or lack
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thereof is kind of what matters not really how shiny it is here is where I
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leared that due to the manufacturing process of direct contact coolers like
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the 212 Evo they're all basically flat
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meaning that the sanding that I did just removed some material and made almost no
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other difference at all so do you think lapping is useless no you probably don't
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and that's a good thing it made no impact when I did it but as
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someone who appreciates science that sample size is bad and if I thought it
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was enough I should probably feel pretty bad not even silent PC review really
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tested a wide enough range of heat sinks in my opinion and I wouldn't expect him
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to we need a community of people for that I suggest you go read the article
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on silent PC review and if you would check out the Forum Link in the video
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description and let everyone in the community know including myself what
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experiences you have had with lapping your CPU or CPU heat sink from reading
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the article it seems that con cave heat sinks are bad flat ones are relatively
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neutral and convex ones have a bit of an advantage thanks to their stronger
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mounting pressure directly over the CPU die as it curves this information has
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led water block manufacturers and enthusiasts to intentionally bow the
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bases of popular blocks in the past like the dtec fusion and apog GT so while we
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don't have anything obviously concave to test for you we hope you still found the
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methodology for lapping we presented useful and we'd love to see your results
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and use the code Linus at the checkout to save $5 on your next purchase of $10
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or more thanks for watching this video guys if it sucked you know what to do
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but if it was awesome get subscribed hit the like button or even consider
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supporting us directly by using our Amazon affiliate code to shop at Amazon
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although you'll probably buy sandpaper at a local shop that's fine buy a cool
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t-shirt like this one or the direct monthly contribution to the porum
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porum with the direct monthly contribution to the Forum now that
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you're wondering what to watch next maybe check out one of the previous
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Workshop videos the the answer to every single one of them is it doesn't matter
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but there's going to be one of them up there so check it
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out