Maybe I should be posting this on a techie forum but questons on here usually get answered fast and I’ve no doubt that there’s more than one person on here who can help with this.
I recently replaced the motherboard on a desktop computer. Since then it has shut off twice because of what it called a “thermal event”. In other words, the CPU is overheating and shutting down the computer to protect itself.
This particular computer has a large heat sink and a large fan that mounts over that heat sink. It had been at least a decade since I last installed a CPU on a motherboard and I wasn’t aware of things like thermal paste and thermal pads so I just slapped it together thinking that was enough. I’ve since read that either paste or a pad are necessary to conduct the heat away properly.
Pads seemed like a less messy alternative so I spent 3 bucks for a package of “phase changing thermal heat sink pads”. Upon opening them I discovered 5 pads a good deal smaller than the surface of the CPU.
Is the smaller size an issue? Some websites say that the pads melt from the heat and fill in microscopic imperfections. When they melt, do they also spread out over the entire surface? If not, would there be a problem with using more than one so as to cover the entire surface?
Should I just buy some thermal paste instead? Can anyone with experience recommend types and brands?
what type of CPU? if it’s a Pentium 4, Intel Core, or Athlon 64/Phenom/Opteron, it should have a heatspreader on it and generic white heatsink paste should be OK. If it’s a Pentium III/Celeron/AthlonXP with a bare CPU die, then a pad is much safer.
ETA: also, if this is an Intel Pentium 4 or Core system which has that heatsink attached by the four plastic pins, make sure the pins are all securely attached. sometimes they can pop out and the heatsink won’t be in good contact with the CPU.
Use thermal grease (paste if you prefer) all the way.
Thermal pads do not have near the performance that the grease does. Thermal pads are best used on other things like memory chips which generally do not get as hot.
I recommend Arctic Silver 5 (no I do not work for them or own stock in them but I have built many computers and this is good stuff). There are other brands out there too but not all thermal greases are created equal. There are a couple other brands that measure up to Arctic Silver 5 but I forget what they are offhand.
When applying the grease first be sure to thoroughly clean the CPU and the heatsink of all traces of the previous grease or pad. Rubbing alcohol works well here and use a lint free cloth (coffee filters work well for this). Be gentle and take your time. It can be a bit tedious but attention to detail here pays off.
When applying the grease do not spread it all over the CPU. Instead put a tiny blob (maybe the size of a grain of rice) in the center of the CPU and set the heatsink down directly on top. The grease will spread itself under the heatsink giving the ideal coverage. Too much grease is not a good idea for a few reasons. You want the layer to be pretty thin. Spreading it manually can leave air gaps as well which is also not ideal.
Also consider your heatsink and what you are using your PC for. Heatsinks are definitely not all created equal. The stock heatsink that comes with an Intel CPU, while better than nothing, is about the worst there is. It is sufficient if all you do is browse the web, get email and so on but not very good for more demanding tasks. Up to you but consider a new, aftermarket, heatsink. Just be certain any heatsink you choose will fit both your motherboard, CPU and in your case. Not all heatsinks will work on all motherboards or CPUs for various reasons. Also, some heatsinks can be huge and will not fit in all cases. Check and doublecheck the specs if you do this. Make sure it doesn’t cover memory slots you are using (happens with some).
Here’s a manual (PDF…just one page) for applying thermal paste. These guys manufacture heat sinks and manufacture what is probably the best heat sink on the market today (I have one and it is awesome). Point being they know what they are talking about.
If it’s one of those, save yourself endless headaches and buy an aftermarket heatsink with a screw plate.
I can’t agree–I get much better results from spreading a very thin layer of paste on the CPU’s contact surface with the edge of a credit card. Especially if you’re using a stock heatsink–I’ve only found the quoted method to work with the best of screw-down heatsinks that have tension springs and all that whatnot.
Regarding thermal pads: follow the package directions. One will do, if the pads are marketed as being for your particular type of CPU.
Fortunately I work near an MEI Microcenter and I think they have Arctic Silver 5 so I can stop by there after work today for the paste/grease and I’ll have a weekend project.
The processor is a dual core Pentium. I don’t have the specifics or the computer in front of me at the moment so I can’t say exactly what processor it is.
It already has a big ass heat sink. There is a metal (I assume it’s metal) square attached on the bottom of it that is the size and shape of the surface of the CPU and fits exactly over it when the sink is screwed onto the board.
folks, I really doubt he’s overclocking. there’s no point to any of these fancy thermal paste application methods. put a blob on there, attach the heatsink, and let the clamping force squeeze it into a thin layer.
Phase change thermal pads (e.g. the “pink” ones) work as well as or better than paste; but only on bare-die chips where the pad has a chance to “change phase” and squeeze into a thin layer. They also have the advantage of adding a bit of a “cushion” to prevent chipping of the processor die.
The point of the thermal grease is to avoid the air gaps between the processor heat spreader/ceramic package/etc… and the heat sink. Air’s a terrific insulator, so your heat transfer will be less than optimal.
Even the best grease doesn’t compare to the conductivity of copper/aluminum, etc… so you want as little grease as you can get away with and still fill in the air gaps.
In the grand scheme of things, the paste’s properties probably aren’t all that important provided you have enough (but not too much) in the right places.
I have never seen anyone claim a thermal pad is superior to properly applied thermal compound.
I will agree that for most average users a thermal pad (the change phase ones) would probably be sufficient and they would never know the difference.
On the upside thermal pads are easier to use than thermal compound when doing an installation (thermal compound can be messy).
On the downside if you ever have to remove the heat sink thermal pads are a PITA. I have had to remove it before and I thought I was going to rip the chip out of the socket (fortunately I didn’t but I have heard of it happening). The pad can sort of weld the heatsink to the chip. Cleaning off old thermal is noticeably harder than cleaning off old thermal compound.
Personally the slightly more difficult task of installing with thermal compound is not all that bad and you get somewhat better performance and have a much easier task if you ever need to remove the heatsink.
Okay, I’ve gotten two opinions on how to apply the compound. Spread it over the surface with a credit card, or just put a small dab in the middle. The small dab method seems to have more proponents.
because the force of the heatsink clamping down will spread it into a thin layer anyway. so there’s no real reason to go through the bother of spreading it yourself.
Also, spreading it yourself you can never make it perfectly smooth. There will be grooves (which could leave air gaps under the heatsink) and thicker and thinner spots. You are also more likely to leave too thick a covering when spreading it manually.
Using a dab tends to avoid those problems. The issue here is too little a dab or too big a dab. I have seen some sites suggest a “pea” sized dab which is waaaay too big. Go with the manual I linked above or judge it to be about a grain of rice (maybe a little smaller).
That said I have done the manual spread method a few times and it worked fine. Personally I find the dab simpler to deal with and it provides better results (usually…any method can be messed up).
I did that once on an old Pentium 4 CPU. I almost didn’t want to turn it over to check how bad the damage was, but miraculously it had gone straight up and none of the pins even got bent. I never want to do it again, though; I figure I probably used up a lifetime of good DIY-luck on that move.
When I looked it up, I was told it depends on the processor which is the better method. I was also told that, if you want maximum cooling right away, you need to prime the heat sink by putting it on with a credit card and wiping off the excess with a coffee filter. Otherwise you will have to wait on the paste to set, which can take a couple weeks.
And, depending on your chip, it may run hot already, so every little bit helps. I know it was a big deal for my off-the-shelf unit, as it apparently had very little margin.
