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[nextpage title=”Introduction”]

Following up on our Thermal Compound Roundup – February 2011 and Thermal Compound Roundup – March 2011 reviews, we are adding five more thermal compounds to our roundup for a total of 15 different models from Antec, Arctic Silver, Biostar, Cooler Master, Coolink, Deepcool, Evercool, Gelid, Noctua, Prolimatech, Spire, Thermalright, Xigmatek, and Zalman. In this review we will see 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, you see the five new thermal compounds we are adding to our roundup.

Figure 1: The new thermal compounds included in this roundup

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

[nextpage title=”The Thermal Compounds”]

We will now take a look at the five new thermal compounds we are including in our roundup. The first compound in this batch is the Antec Thermal Grease, shown in Figures 2 and 3. It is a white compound, comes with three one-gram bags, and is made by the Taiwanese company Sil-more.

Figure 2: Antec Thermal Grease

Figure 3: Antec Thermal Grease

Figure 4 shows an extremely popular product, which many readers asked for in this roundup: the Arctic Silver 5 thermal compound, which has a dark gray color.

Figure 4: Arctic Silver 5

The third competitor is the Arctic Silver Céramique white thermal compound.

Figure 5: Arctic Silver Céramique

[nextpage title=”The Thermal Compounds (Cont’d)”]

We also tested the Biostar Nano Diamond dark gray thermal compound, shown in Figures 6 and 7. Its color is dark gray. There is a potential issue in this thermal compound packaging: the syringe is labeled with a "for single use" warning, which may mislead the user to immediately apply all of the compound on his or her CPU.

Figure 6: Biostar Nano Diamond

Figure 7: Biostar Nano Diamond

In Figures 8 and 9 you see the Xigmatek PTI-G3606 thermal compound.

Figure 8: Xigmatek PTI-G3606

Figure 9: Xigmatek PTI-G3606

For a detailed look at the other thermal compounds included in this roundup, please check our Thermal Compound Roundup – February 2011 and Thermal Compound Roundup – March 2011 reviews.

[nextpage title=”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.

Figure 10: 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.

Figu
re 11: 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 °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
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

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.

[nextpage title=”Conclusions”]

Now we have 15 different thermal compounds in our review, and the conclusions are the same: some thermal compounds are better than others, but the difference is not significant, at least not with the models we included so far. Of course, if you have a cooler with a rougher base, probably the impact of a good thermal compound will be bigger than with a mirror-like base such as the one we used. We will continue to add more thermal compounds to our roundup and publish our findings.