# Heatsink thermal interface material question **URL:** \ **Category:** Factual Questions\ **Created:** [July 12, 2009, 6:09pm UTC](https://boards.straightdope.com/t/heatsink-thermal-interface-material-question/502772 "2009-07-12T18:09:06Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Thinktank](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Thinktank](https://boards.straightdope.com/u/Thinktank)\ **Post date:** [July 12, 2009, 6:09pm UTC](https://boards.straightdope.com/t/heatsink-thermal-interface-material-question/502772/1 "2009-07-12T18:09:06Z")
Hi, For those that don’t know what I’m talking about, sorry but it’s a geeky computer hardware question. Ok, now that the room has cleared out some:D. I am computer tech… I’ve worked with computer hardware for 4 years now, but often just get into doing the job and not asking so many questions. Anyway, I was removing a laptop heatsink the other day to migrate the processor to the new board when I started to wonder all about the fact that the CPU always has a thermal grease bond, but the video chipset seems to always have a blue thermal pad situated over it. The question is … why? Would it not be just as easy (for the manufacturer) to form the heatsink so that when screwed-down there was less of a gap between the heatsink and the video chipset -and then also bond _this_ contact point with thermal grease as well? You see, I’m not just thinking aloud, I did try and unravel this question myself with google and read that in every case thermal grease was the better option for dissipating heat. As an addendum to my question, if anyone can tell me what these spongy blue pads are made of I’d appreciate an answer. Thanks in advance everyone. ---
**Author:** ![JKilez](https://avatars.discourse-cdn.com/v4/letter/j/e5b9ba/32.png) [@JKilez](https://boards.straightdope.com/u/JKilez)\ **Post date:** [July 12, 2009, 7:21pm UTC](https://boards.straightdope.com/t/heatsink-thermal-interface-material-question/502772/2 "2009-07-12T19:21:06Z")
Are you talking about the spongy pad that _surrounds_ the GPU, or a thermal pad on the GPU itself? If you are talking about the latter, your experience is not the same as mine. I have removed numerous heatsink/fan combos from graphics cards (primarily NVidia based) and have only ever seen thermal paste used. On a side note, AMD used to recommend thermal pads instead of paste for their _CPU_s and some of their retail units used them, but I could not say how widespread this was or is. ---
**Author:** ![SmashTheState](https://avatars.discourse-cdn.com/v4/letter/s/e36b37/32.png) [@SmashTheState](https://boards.straightdope.com/u/SmashTheState)\ **Post date:** [July 12, 2009, 7:33pm UTC](https://boards.straightdope.com/t/heatsink-thermal-interface-material-question/502772/3 "2009-07-12T19:33:43Z")
My understanding is that the reason certain video card manufacturers use those worthless thermal pads is because they have a contract with the maker. I always replace those thermal pads with Arctic Silver when I buy a new computer. I’ve known too many people who have their video chipsets die two days past the warranty as a result of excessive heat while relying on thermal pads. ---
**Author:** ![Thinktank](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Thinktank](https://boards.straightdope.com/u/Thinktank)\ **Post date:** [July 12, 2009, 7:40pm UTC](https://boards.straightdope.com/t/heatsink-thermal-interface-material-question/502772/4 "2009-07-12T19:40:29Z")
> [@JKilez](#): > > Are you talking about the spongy pad that _surrounds_ the GPU, or a thermal pad on the GPU itself? If you are talking about the latter, your experience is not the same as mine.. Ah, I guess I should have mentioned that about 98% of the laptops I work on are of the same brand. But in any case I scooped an image out of google to remove all doubt of what I’m referring to. Click[HERE](http://i21.ebayimg.com/05/i/001/22/22/e0cd_1.JPG) Btw, anyone wanna earn extra points and answer the “material composition” question about the spongy pads? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 12, 2009, 8:17pm UTC](https://boards.straightdope.com/t/heatsink-thermal-interface-material-question/502772/5 "2009-07-12T20:17:56Z")
There are a zillion different types of thermal pads; [here](http://www.dowcorning.com/applications/search/default.aspx?R=1780EN&DCCSF=1968EN&DCCSF=21EN) is data from a typical product. The key to all thermal pads is this: they are gap-filling. Unlike thermal paste, these pads can fill sometimes substantial gaps between the IC and the heatspreader. I would be VERY wary about replacing a pad with paste, unless I was absolutely sure that the fit was gap-free and smooth. ---
**Author:** ![Thinktank](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Thinktank](https://boards.straightdope.com/u/Thinktank)\ **Post date:** [July 12, 2009, 8:30pm UTC](https://boards.straightdope.com/t/heatsink-thermal-interface-material-question/502772/6 "2009-07-12T20:30:31Z")
> [@beowulff](#): > > There are a zillion different types of thermal pads; [here](http://www.dowcorning.com/applications/search/default.aspx?R=1780EN&DCCSF=1968EN&DCCSF=21EN) is data from a typical product. Fixed your link Beowulff ;). Click [HERE](http://www.dowcorning.com/applications/search/default.aspx?R=1780EN&DCCSF=1968EN&DCCSF=21EN)