Introduction

Following up on our Thermal Compound Roundup - April 2011 review, we are adding five more thermal compounds to our roundup, for a total of 20 different models from Antec, Arctic Cooling, Arctic Silver, Biostar, Cooler Master, Coolink, Deepcool, Evercool, Gelid, Noctua, Prolimatech, Spire, Thermalright, Thermaltake, Tuniq, Xigmatek, and Zalman. In this review we will determine if certain products are superior to others.

For a better understanding of how the thermal compound (a.k.a. thermal grease or thermal paste) works and how to correctly apply it, please read our How to Correctly Apply Thermal Grease tutorial. The most important concept that you must understand is that it is a mistake to think that the more thermal grease you apply, the better. The thermal compound is a worse heat conductor than copper and aluminum (the metals usually found on cooler bases). So, if you apply more thermal compound than necessary it will actually lower the cooling performance instead of improving it.

In Figure 1, there are the five new thermal compounds we are adding to our roundup.

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Figure 1: The new thermal compounds included in this roundup

Figure 2 shows all the syringes of the thermal compounds we tested so far.

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Figure 2: The thermal compounds compared so far

Let's get a closer look at the new contenders in the next pages.

The Thermal Compounds

We will now examine the five new thermal compounds we are including in our roundup.

Figures 3 and 4 illustrate the Antec Formula 7 gray compound.

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Figure 3: Antec Formula 7

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Figure 4: Antec Formula 7

Figures 5 and 6 show the Arctic Cooling MX-4 thermal compound, which also has a gray aspect.

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Figure 5: Arctic Cooling MX-4

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Figure 6: Arctic Cooling MX-4

The Thermal Compounds (Cont’d)

We also tested the Cooler Master High Performance Thermal Compound, shown in Figures 7 and 8. It is the only white compound in this batch.

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Figure 7: Cooler Master High Performance

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Figure 8: Cooler Master High Performance

Figure 9 displays the Thermaltake thermal compound, which came with the Silent 1156 CPU cooler.

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Figure 9: Thermaltake thermal compound

Figure 10 shows the last contender for today: the Tuniq TX-3 thermal compound.

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Figure 10: Tuniq TX-3

For a detailed look at the other thermal compounds included in this roundup, please check our Thermal Compound Roundup - April 2011 review.

How We Tested

We tested the thermal compounds using the same testbed system that we currently use to test CPU coolers, which is fully described below. Our Core i7-860 (quad-core, 2.8 GHz) CPU, which is a socket LGA1156 processor with a 95 W TDP (Thermal Design Power), was overclocked to 3.3 GHz (150 MHz base clock and 22x multiplier), and we kept the standard core voltage (Vcore). We used a Zalman CNPS9900 MAX CPU cooler. The only different part in each test was the thermal compound itself.

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 applyied the same quantity of thermal compound (about the size of a grain of rice) at the center of the CPU, as shown in Figure 10.

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Figure 11: Applying thermal compound

After each test, we checked the base of the cooler, making sure the quantity of thermal compound was optimal. The thermal compound must be spread evenly on the metallic part of the CPU, without exceeding it, creating a thin layer. The "fingerprint" shown in Figure 11 illustrates that the compound was properly applied.

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Figure 12: CPU "fingerprint," showing the thermal compound was correctly applied

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.

We also tested the system with no thermal compound on the CPU.

Hardware Configuration

• Processor: Core i7-860
• CPU Cooler: Zalman CNPS9900 MAX
• Motherboard: Gigabyte P55A-UD6
• Memory: 2 GB Markvision (DDR3-1333/PC3-10700 with 9-9-9-22 timings), configured at 1,200 MHz
• Hard disk: Seagate Barracuda XT 2 TB
• Video card: Zotac GeForce GTS 250
• Power supply: Seventeam ST-550P-AM
• Case: 3RSystem L-1100 T.REX Cool

Operating System Configuration

• Windows 7 Home Premium 64 bit

Software Used

• Prime95
• SpeedFan

Error Margin

Since both room temperature and core temperature readings have 1 ^oC resolution, we adopted a 2 ^oC error margin, meaning temperature differences below 2 ^oC are considered irrelevant.

Our Tests

The table below presents the results of our measurements.

Thermal Compound	Room Temp.	Core Temp.	Difference
No Thermal Compound	26 °C	88 °C	62 °C
Zalman ZM-STG2	24 °C	59 °C	35 °C
Prolimatech Thermal Compound	24 °C	56 °C	32 °C
Cooler Master Thermal Compound Kit	23 °C	58 °C	35 °C
Evercool EC420-TU15	22 °C	57 °C	35 °C
Spire Bluefrost	22 °C	58 °C	36 °C
Gelid GC Extreme	26 °C	61 °C	35 °C
Coolink Chillaramic	26 °C	61 °C	35 °C
Deepcool Z9	26 °C	61 °C	35 °C
Noctua NT-H1	26 °C	61 °C	35 °C
Thermalright The Chill Factor	26 °C	63 °C	37 °C
Antec Thermal Grease	24 °C	58 °C	34 °C
Arctic Silver 5	24 °C	57 °C	33 °C
Arctic Silver Céramique	24 °C	57 °C	33 °C
Biostar Nano Diamond	22 °C	57 °C	35 °C
Xigmatek PTI-G3606	22 °C	55 °C	33 °C
Antec Formula 7	21 °C	55 °C	34 °C
Arctic Cooling MX-4	21 °C	56 °C	35 °C
Cooler Master High Performance	22 °C	56 °C	34 °C
Thermaltake Thermal Compound	21 °C	54 °C	33 °C
Tuniq TX-3	22 °C	54 °C	32 °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.

Conclusions

The results of our tests remain consistent with the data and the conclusions we took so far: on a system like the one we used to compare the thermal compounds, the model and brand make little difference in the CPU temperature.

However, the five Celsius degrees difference between the best and the worst results are relevant for people who care about their CPU temperature and want to squeeze every possible degree. So, if you fit this description (most overclockers do) you can have an idea about which product you can look for.

We will continue to test more thermal compounds, so stay tuned!