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I was told many years ago to do this by someone who at the time knew more than I did. The CPU was a celeron in the Pentium 2 era. It ran cooler with the toothpaste between the chip and the heatsink than what it did with nothing between.

Has anyone else ever heard of or tried this? What were the results?

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...just when you think you've seen it all –  Manos Dilaverakis Jan 29 '10 at 11:36
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The other question to consider is whether you can brush your teeth with thermal paste. That would be good for teeth.stackexchange.com... –  Yar Jan 29 '10 at 11:57
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No idea if this would work to be honest, but at least your CPU would be protected against plaque build-up and gingivitis. –  Kez Jan 29 '10 at 12:16
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Thanks a lot. Now I've sprayed coffee out of my nose and down my shirt. –  njd Jan 29 '10 at 14:36
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Send me your CPUs and I'll test them for you! I've currently got gell, baking soda, triple action and plain toothpaste, so 4 CPUs should be enough. –  Ash Jan 30 '10 at 2:17

7 Answers 7

up vote 57 down vote accepted

This is the standard "saran-wrap-in-place-of-condom" question. While some toothpastes may provide the correct type of thermal conductivity, "toothpaste" is too big a category to answer the question accurately. Worse, unless you want to make it a fun science project, nobody is going to be testing different types of toothpastes for thermal conductivity.

That said, the answer is probably "yes." Toothpaste is definitely better than nothing, because air (i.e., nothing) is a terrible heat conductor. That said, there are other properties to consider. From Wikipedia

  • How well it fills the gaps and conforms to the component's uneven surfaces and the heat sink
  • How well it adheres to those surfaces
  • How well it maintains its consistency over the required temperature range
  • How well it resists drying out or flaking over time
  • How well it insulates electrically
  • Whether it degrades with oxidation or breaks down over time

I think that toothpaste might work for the thermal part, but you might have other problems in the short- or long-run.

On A Different Note: That said, if you need to stick a note to the wall, you can definitely use chewing gum (after chewing a bit). Sometimes it's hard to get off when your lease is over, though :)

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@RichieACC, thanks, I edited a bit too to try to make it funnier. –  Yar Jan 29 '10 at 11:53
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@RichieACC, I don't know, but I would say to get sugarless. Sugar tends to change over time, attract insects, etc. –  Yar Jan 29 '10 at 11:58
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Also, don't use thermal paste for your teeth. –  skarface Jan 29 '10 at 15:34
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If you find yourself in a "server needs to be up in 5 minutes" situation with the processor in your hand you've really already lost. I can just imagine the postmortem on the hardware a few months later... "What's this all over the... toothpaste?!?!" In all reality though, get yourself a non-stick frying pan, put some toothpaste on it and see at what temperature it a) liquefies and b) smokes. If either happens under 150 degrees (F) you better off with nothing. –  Rob Allen Jan 30 '10 at 1:00
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@Rob Allen, thanks man, please don't delete, this conversation should remain in the annals of Superuser forever. TRue about the toothpaste and temperature. Also true that a few months later you'll have forgotten about putting the toothpaste there, and then you're really screwed. –  Yar Jan 30 '10 at 1:59

It might be better than nothing, but unless toothpaste has unsuspected thermal conductivity, I'd say it's a bad idea.

You also have to consider what the ingredients of the toothpaste might do in contact with your CPU. I suspect it would be pretty conductive in an electrical sense. You don't want electrical conductivity.

Better get some real thermal paste. It's more expensive than toothpaste, but worth it.

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+1 better than nothing, but certainly no replacement –  William Hilsum Jan 29 '10 at 11:54
    
Water is excellent at transferring heat, but the toothpaste will dry up in a week or so. –  Cees Timmerman Jan 7 at 13:06
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@CeesTimmerman Surprisingly, it continues to conduct heat just fine even after it dries up. You wind up with dicalcium phosphate with some moisture still trapped and it retains substantially the thermal conductivity of water. It is vulnerable to cracking, but so are many thermal compounds. Corrosion is a risk though. –  David Schwartz Mar 11 at 0:43
    
@WilliamHilsum, @ pvium, but could it actually make things worse off? –  Pacerier Jun 18 at 10:21

I remember hearing about this at Dan's Data a while back, and he went back and forth with Arctic Silver's Nevin on the issue.

I think the basic idea was that toothpaste will dry up faster than true thermal paste, perhaps leaving you a lot worse off than if there was nothing at all. So, if you like removing your heatsink as much as I do, then no, it's not ok.

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Whew!! I was beginning to think that nobody else had heard about this and that I was a victim of a rather mean prank! Oh, wait, this does not exclude that as a possibility :) –  RichieACC Jan 29 '10 at 12:01
    
brilliant icon, hyperslug. Good answer too –  Yar Jan 29 '10 at 13:30

I've been using a rebuild with toothpaste on my Thinkpad T42 for about 3 years, with no problems. These laptops, however, are known for running cooler than most thinkpads, to begin with, and we don't play very many 3-D games on those ATI 9600's, so the load on the toothpaste is not very high. If you are worried about the paste drying out, just use A LOT. The only part that will dry out is the stuff on the edges of the CPU, and if you are generous with the paste, there should continue to be a large amount in the middle of the CPU that is thoroughly wet ... or use 25% vaseline and 75% paste... or 25% grease and 75% paste. Grease is basically oil & soap, to keep the oil from drying out.

Remember, toothpaste drops the temperature by 20 degrees, even after 12-hours of burn-in, and arctic silver 5 drops it by 29 degrees at most. So toothpaste gets you 69% to cooling nirvana, even after the dry-out period.

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So your room is filled with toothpaste smell? –  Pacerier Jun 18 at 10:23

I put tooth paste between the heat sink and the CPU with the Colgate Total Advanced... It works like a champ!

If there will be an issue in the future, the PC knows how to protect itself, and it shut it off.

I used it on my 5 years old computer that I didn't care too much.

So far, again, it works great. I spread the paste with an old credit card, and cleaned the old paste with Lysol before I applied the tooth paste.

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Good to hear. What are the temps of the toothpaste compared to the thermal paste under load and idle? This page says it's better than 8-year-old stock goop, but doesn't last long. –  Cees Timmerman Jan 7 at 11:47
    
@CeesTimmerman thanks for that page, I'm giggling like an idiot in a half-deserted office. –  spacecrab 7 hours ago

Also just used toothpaste on my macbook pro 2011. It had a failing graphics card and being out of warranty I waited until it was truly dead => no boot. I took it apart, cleaned it and removed all plastic. Did a "reflow" of the motherboard in our regular oven at 220 degrees Celsius for a couple of minutes. Applied toothpaste to the cpu and gpu and put it all back together.

After all this it booted right back up. It ran hot for 2 minutes at 90 degrees Celsius. (might have been a diagnostic check after being taken apart, OSX just testing the insides) It now runs at 45 degrees Celsius under normal load. No crashes, no funky broken graphics cards stuff anymore.

It will probably set itself on fire at some point, but more likely because of the failing battery then because of the toothpaste.

Just to be clear: this is an old machine that has been abused for many years. I work as a photographer and this is the machine that travelled with me. So it saw lot's of water, dust, sand, mud and everything you don't want around electronics. Do not try this just because you are too lazy to get the real stuff.

Only badasses may proceed!

Update:

The gpu finally truly died. Well not really, the gpu is perfectly fine, even after months of having toothpaste for thermal paste. The solder connecting it to the motherboard however has too many cracks in it now and a reflow in a cooking oven no longer works.

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Wouldn't the toothpaste melt? –  Pacerier Jun 18 at 10:23
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No it dries up at the edges after a while –  R Menke Jul 6 at 9:44

You acutally would be surprised.

In a pinch, yes, it is OK but a pinch is basically 12 hours.

If you want some other common goods, try this:

http://forums.overclockersclub.com/topic/164465-you-got-your-peanutbutter-on-my-cpu-you-got-your-cpu-in-my-peanut/

http://forums.overclockersclub.com/topic/164465-you-got-your-peanutbutter-on-my-cpu-you-got-your-cpu-in-my-peanut/?p=1680970

All of these ideas will help you in a pinch but ALWAYS get proper thermal paste.

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