cpu - Thermal Paste in a Laptop quickly loses efficiency
2014-04
LTR
Some time ago, I removed the thermal pad from my CPU and applied some thermal paste instead. I also removed dust from the fan. It's a Dell Studio 1735 Laptop. The laptop got MUCH quieter and cooler.
Three months later, it's loud and hot again.
There is no dust. I just removed the cooler, and all of the thermal paste still sits there. Maybe while travelling, the CPU cooler wiggled around a microscopic amount, thereby reducing the effectiveness?
How do I apply the thermal paste so that the cooling efficiency persists? Could it be that a thermal pad would work better in the case of a laptop, as it is rigid and won't move under mechanical stress?
Update: Re-applied thermal paste today, temperatures dropped from about 50°C to 40°C in Idle. Let's see how long that lasts.
168335
The link below has a detailed explanation along with specs.
http://www.insidemylaptop.com/apply-thermal-grease-laptop-processor/
Toneloc427
I'm not sure if this applies to laptops, and your situation in particular, but typically when we see thermal pads on motherboards, they're there to ensure proper contact, usually with a slight "interference" fit. When switching to grease, you may not have enough height to compensate for the loss of the pad.
Was the pad truly a pad, or just "pre-applied" grease? If the former, you may need to modify some part of the heat sink or find a pad of similar thickness to the original.
RichieACC
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?
Yar
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 :)
pavium
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.
hyperslug
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.
user26528
If it ran cooler why isn't using toothpaste more common? Perhaps the person who told you this was a dentist and had a bias opinion. If you want to keep your CPU safe and cool for a long time, use thermal paste. If you want to protect it from cavities and gingivitis, by all means, Colgate Total is the best option.
systemBuilder
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.
Yossi
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.