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In our Thermal Compound Roundup – May 2011 review, we compared 20 different thermal compounds from several brands. Some readers asked us to include the thermal compound that comes with stock coolers (the thermal solutions that comes with in-a-box CPUs) in the comparison, in order to answer the question "is it necessary to change the thermal compound that comes preapplied on a retail product?"
In order to answer this question, we will test the cooling performance of an Intel stock cooler that came with a Core i3 CPU (shown in Figure 1) with the original compound, and then with some other thermal compounds to see if we found some performance improvement.
Let’s find out which thermal compounds we compared and the test results in the following pages.
[nextpage title=”The Thermal Compounds”]
The thermal compound that comes on the Intel stock cooler is applied in three stripes, as you can see in Figures 2 and 3.
We will compare the performance of this compound to the results with the Arctic Silver 5, Arctic Cooling MX-4, Prolimatech, and Gelid GC Extreme thermal compounds. You can learn more about those products in our Thermal Compound Roundup – May 2011 review.
[nextpage title=”How We Tested”]
We tested the thermal compounds on a Core i3-540 CPU (3.06 GHz), overclocked to 4.0 GHz (23 x 174 MHz) in order to produce a little more heat. We used the stock cooler that comes with this CPU, first using the preappyied thermal compound. Then we removed the cooler, cleaned the CPU and cooler base surfaces, applied a different thermal compound and then tested again. This procedure was repeated for each retail thermal compound used.
We measured temperature with the CPU under full load. In order to get 100% CPU usage in all threads, we ran Prime 95 25.11 (in this version, the software uses all available threads) with the "In-place Large FFTs" option. For each test, we applied the same quantity of thermal compound (about the size of a grain of rice) at the center of the CPU.
The first conclusion was that the stock thermal compound spreads very well, as you see in Figure 4.
Room temperature measurements were taken with a digital thermometer. The core temperature was read with the SpeedFan program (available from the CPU thermal sensors), using an arithmetic average of the core temperature readings. During the tests, the left panel of the case was open.
- Processor: Core i3-540
- CPU Cooler: Stock cooler
- Motherboard: Gigabyte H55M-S2H
- Memory: 4 GB OCZ (DDR3-1600/PC3-12800 with 8-8-8-24 timings), configured at 1,400 MHz
- Hard disk: Seagate Barracuda XT 2 TB
- Video card: Integrated video
- Power supply: 3R System iCEAGE IA500HP80 500 W
- Case: GMC R-2 Toast
Operating System Configuration
- Windows 7 Home Premium 64-bit
Since both room temperature and core temperature readings have 1 °C resolution, we adopted a 2 °C error margin, meaning temperature differences below 2 °C are considered irrelevant.
[nextpage title=”Our Tests”]
The table below presents the results of our measurements.
|Thermal Compound||Room Temp.||Core Temp.||Difference|
|Intel stock thermal compound||18 °C||89 °C||71 °C|
|Gelid GC Extreme||15 °C||86 °C||71 °C|
|Prolimatech Thermal Compound||17 °C||90 °C||73 °C|
|Arctic Cooling MX-4||15 °C||89 °C||74 °C|
|Arctic Silver 5||18 °C||93 °C||75 °C|
In the following graph, at full load you can see how many degrees Celsius hotter the CPU core is than the air outside the case. The lower this difference, the better is the performance of the thermal compound.
The original compound is a high-quality one, and it comes optimally applied. None of the compounds we tested performed better than the stock compound; in some cases, good products had worse performance than the stock compound.
Note that the comparative performance between the retail thermal compounds was not the same as in our Thermal Compound Roundup – May 2011 review. This is not an issue, but rather a characteristic of the cooler we used. Actually, the stock cooler doesn’t have the same pressure as the cooler we used on the previous comparison. It seems logical that thermal compounds with different viscosities behave differently under varying pressure conditions.
The test results are crystal clear. There is no point in wiping off the thermal compound that comes preapplied on the Intel stock cooler and replacing it with a different compound, at least when using a mainstream CPU.