Thermal compounds round-up : Part One

Posted by: Wicked Akuba Date: 2009-07-23 13:33:17
Category: Cooling

I am the person, who gets involved with PC cooling products, such as CPU or VGA coolers, fans and thermal interface materials most often in our team. Today I'm going to explore the last item on the list - TIMs. To be exact, for the first part of our TIM roundup (the second one will follow shortly), we will be looking at 8 different products from 6 manufacturers: Antec Formula 5, Coollaboratory MetalPad ir Liquid Pro, Coolink Chillaramic, Gelid GC-2 and GC-Extreme, Noctua NT-H1 and Scythe Thermal Elixer.





Contents:

>About thermal grease
>Competitors:
Antec Formula 5
Coollaboratory MetalPad
Coollaboratory Liquid Pro
Coolink Chillaramic
Gelid GC-2
Gelid GC-Extreme
Noctua NT-H1
Scythe Thermal Elixer
>Testing methodology
>Results

About thermal compound

Our most loyal readers should know a bit about cooling, if they read an article about cooling at Technews.lt, written by my colleague Dovydas. By citing it I would like to explain what is thermal grease or thermal interface material and why is it important.

A very important thing for every cooler is its ability to contact with the heat generating surface. The better those two surfaces contact, the better the heat is transferred to the cooler, where eventually it is dissipated. Because it is nearly impossible to ideally polish neither the cooler's nor the CPU's base, microscopic gaps between the two surfaces are always being created. Because the air in the gaps acts like an isolator of heat, it is important to fill the gaps with something that has a much greater thermal conductivity than air. And that something is a thermal interface material.

Sooner you could find TIMs, which were based on silicon, ceramic or metal (usually silver) powder (from the worst to the best) and quite confidently, after taking into account the thermal conductivity specifications, choose a TIM, which would work pretty much as you would expect. Now, as the manufacturing technologies evolve and new materials (various metal oxides) are being used, choosing the right product is becoming quite difficult and only the specifications can be misleading. Users, who choose a compound with metal particles should note, that such TIMs are a bit electrically conductive, which means, that it should be used carefully on chips without an IHS.

Despite the quality of thermal interface material, its thermal conductivity will never by greater than the direct ideal contact between the CPU and the cooler. That's why you should use only a small amount of TIM (a dot with diameter of about 2 mm; this number can vary depending on the CPU's and cooler's surface) and although the excess grease is usually squeezed ant pushed through the sides of the CPU, but it will make a mess around the CPU socket and the remaining grease might not give the optimal performance. Some of the manufacturers recommend to spread the TIM on the CPU (plastic cards are very suitable for this task), while others don't, saying, that the grease will be spread by the cooler itself. By only changing the TIM to a better one in some cases you can win about 2 to 5 degrees or more off of your CPU temperature.

If you want to change the TIM on the CPU, you have to clean the old one first. And because after a longer period the grease sometimes hardens, wiping it off with only a paper towel may seem quite difficult. For cleaning off the TIM you can buy a special liquid cleaner, but actually the majority of cleaners, including a high percentage of alcohol (because of its short evaporation time) will get the job done. After that the CPU should be cleaned with a dry paper towel to remove any remaining traces of the cleaner.


Antec Formula 5

Besides cases or power supplies Antec also has some other products including TIMs. Today we are looking at the Antec Formula 5, which is based on silver particles and sold in a rather big diameter tube. According to the manufacturer, the silver makes 88% of the grease mass. Antec states, that the thermal conductivity of this TIM is greater than 350000 W/m°C. The Formula 5 has a dark grey colour, which, in certain lighting conditions, may look like brown. This product is quite viscous, which is not a very good property for spreading the TIM on the surface. You may encounter some difficulties if you try to look for it in Europe, but in the US a tube of Antec Formula 5 costs around 10 USD.

Coollaboratory MetalPad

You can't really call the Coollaboratory MetalPad a thermal compound. The most accurate definition for this product would be "a flexible metal plate which is added between the CPU ant and the cooler”. If you want to apply the MetalPad, you need to cut a plate of it the size of the CPU. According to the manufacturer, you need to burn in this TIM to at least 60 degrees Celsius in order to achieve the best performance. At this temperature the MetalPad transforms from its solid state to liquid. This product is obviously electrically conductive. Because of the almost unchanging consistence, it is best to use this product with coolers, that have a smooth base, so in today's testing, where an HDT cooler is being used, the MetalPad might not show its best results. Coollaboratory offers the MetalPad in various packages, but you will get the best value if you choose the package with three plates, that costs 8,68 Euros.

Coollaboratory Liquid Pro

This is another innovative product from Coollaboratory. The Liquid Pro, just like the MetalPad is not a conventional thermal interface material. Liquid Pro is basically liquid metal, which, of course, offers very high heat conductivity, but also has a few drawbacks. The first of them is difficult application on the processor. The manufacturer recommends using cotton for spreading it, but I found it much easier to use a needle for that. Despite that I still managed to get some Liquid Pro between the pins of the CPU socket. For my relief, after one hour of cleaning, the computer worked just fine. The syringe with 1 g of Liquid Pro, according to Coollaboratory, will be enough for two times. You’ll have to pay 6,68 Euros for it in Europe.

Coolink Chillaramic
TheCoolink Chillaramic has two features, which makes it stand out of the other competitors. The first one – it has ceramic particles, ant the second – it sells in a big tube, which carries 10 grams of the TIM. It is also interesting, that this compound doesn’t need a burn-in period and can show the best results right after applying it. The consistence of the white colored Chillaramic is convenient for applying and cleaning. This product has a density of 3,2 g/ml, and costs form 6,90 euros for a single package.

Gelid GC-2

The Gelid GC-1 TIM, which showed great performance, is now being replaced by the GC-2 and the GC-Extreme. The GC-2 is a budget TIM, aiming at users, who are looking for a cheaper compound. The GC-2 is also selling in large tubes, with a net content of 7 g. Along with the tube you'll also find a plastic applicator, which helps to spread the quite thick GC-2 grease on the surface. This product is quite hard to apply, because it's just not sticking on the CPU, even when using the applicator. You can get the 7 g tube of the Gelid GC-2 for 4,99 Euros.

Gelid GC-Extreme

Just like the name suggests, this product is oriented for enthusiasts, looking for the best performance. There is only half the amount of the grease in the tube compared to the GC-2, and the consistence is noticeably thinner and thus the TIM is easier to apply and spread it on the CPU. It is also fairly viscous and sticks well both on the CPU and the heatsink. Besides the price of 6,99 Euros and net weight, no other specifications are listed by the manufacturer.

Noctua NT-H1

The readers of Technews.lt know the Austrian company Noctua and its TIM NT-H1 quite well, because this product is being used in all our cooler reviews. Maybe it's time for a change? The NT-H1 has a viscosity that is very convenient for spreading it on the surface and is easy to clean after using, which comes in handy when you need to change the components often. This TIM from Noctua has a density of 2,49 g/ml and there is the usual amount 3,5 gram in the tube. This means, that 1,4 ml of the NT-H1 costs about 6,50 euros.

Scythe Thermal Elixer

Thermal Elixer is a quite fresh product from a well known computer cooling parts manufacturer Scythe. This thermal interface material is being sold in identical to the Gelid GC-Extreme and Noctua NT-H1 syringe-like tubes with 3,5 grams of the grease. According to the manufacturer's website, this TIM has a thermal resistance of 0.032°C/W. The consistence of it is very like the GC-Extreme’s, though it's a bit more difficult to apply it on to the CPU. The smallest price of Thermal Elixer in Europe is 5,73 euros.

>Testing methodology

In today's testing we are using a little different methods than in our previous reviews of cooling products. During the tests the Chieftec Dragon CH-07B-B case was closed and, in order to be more accurate, the ambient temperature was measured after every test. The CPU was cooled by the Xigmatek S1283 CPU cooler with the Crossbow mounting kit and a Noctua NF-P12 fan. We tested each every TIM two times - after 10 minutes CPU load with Prime 95 the temperatures of the CPU were measured with the RealTemp 3.00 software.

Computer configuration:

CPU: Core 2 Duo E6550 1,5 V 3150 MHz (450 MHz x7)
MB: AsRock 4Core1600Twins-P35
VGA: XFX HD4850 XXX 512 MB
RAM: Corsair TWIN2X2048-6400C4 2 GB
Case: Chieftec CH-07B-B
HDD: Samsung HD403LJ; WD SE16
PSU: Chieftec 350 W
ODD: Samsung DVD±R/RW Writemaster SH-S162A


It's time to bust the myth, which is quite alive. The thermal sensors inside the CPU core are very accurate and do not produce apparent errors in the results. The easiest way to apply the compound on a cooler with HDT technology is by adding two parallel lines of the TIM on to the base. Despite that, we spread the TIM on the whole CPU IHS and only then mounted the heatsink, in order to achieve the best accuracy.

>Results

First run



Second run



Average