You've all heard of Thermal Interface Material (TIM) paste and probably used it too, when mounted a CPU cooler to your CPU, but do you know what makes a good TIM compound and how you can compare them? Two of the most known brands are Grizzly and Arctic. I've used both earlier myself. Especially Grizzly is popular today and used by several youtubers and expert authorities on PC building, for instance Der8auer. So just follow his example and do as he's doing, right? Yes, sure, you can do that and chances are you'll be happy with the result, but Grizzly TIM comes in different variants you may want to look at, and there are other alternatives on the market too.
Why do we need to apply TIM?
If you already know this, just skip to the next paragraph, but otherwise a little background about TIM may be fitting to re-iterate here. If we look at a PC's Central Processing Unit (CPU) today, it's covered with a metallic lid that serves as a heat spreader for the actual CPU beneath it. This heat spreader lid looks pretty smooth for the naked eye, but if you look at it in a microscope it's lots of hills and valleys, really. And since heat transfers poorly through air, these valleys need to be filled with TIM to optimize the heat transfer to the CPU cooler, otherwise the CPU cooler only makes contact with the heat spreader on the hilltops. The same goes for the base of the CPU cooler. It may look smooth and shiny to the naked eye, but really isn't as good as it looks. You can lap it with various polishing utilities and make it even better looking — and more effective — but in the end you'd need to add some TIM anyway.
What's a good TIM then?
A good TIM is a compound that transfers heat satisfactory from the heat source to the cooler device. What you, the user, deems satisfactory is of course the key here. You may be satisfied if your CPU doesn't reach temps above 70 degrees Celcius, when stressed in gaming. Or maybe you want it to be lower than that. That's when you'd want to look at alternatives before you decide what TIM to buy.
Thermal conductivity is measured in watts per meter-Kelvin or Wm-1K-1, W/(m*K) or simply W/mk. Without going into the intricate physics here, suffice to say — the higher the W, the better the conductivity, so you'd want to look out for a TIM with a high W/mk. A 5W/mk is better than a 3W/mk TIM. A 12W/mK TIM is better than a 7W/mk. Another factor in TIMs is thermal restistance. This value should be as small as possible.
If you had pure 24K gold then you'd have the best TIM in the world, and also the most expensive. There are some TIMs that are liquid metal though and one such TIM I know of has 40W/mK. It's expensive, but the price is bearable. Grizzly has liquid metal TIM with 73W/mk. However, I don't recommend liquid metal TIM because it will liquify when heated up and run if applied on a vertical surface. That may lead to short circuiting other components the TIM drips upon. Liquid metal TIM is only used on a flat, horizontal surface and should only be applied by an expert. So let's look at more normal TIMs, for everyone's daily use.
Some TIM examples
|Dow Corning/DOWSIL TC-5625||2.5W/mk|
|NAB Cooling NB Max Pro||8.5W/mk|
|Cooler Master MasterGel Pro v2||9W/mk|
|ProlimaTech PK-3 Nano Aluminum||11.2W/mk|
|Thermal Grizzly's Kryonaut||12.5W/mk|
|Thermal Grizzly Kryonaut Extreme||14.2W/mk|
|Alphacool Apex (my favorite)||17W/mk|
Read also: Best Thermal Paste for CPUs 2023: 90 Pastes Tested and Ranked (Tom's Hardware)