Geek Tested: 17 Thermal Pastes Face Off
Does thermal paste really matter? We applied, reapplied, reapplied some more, and turned up the heat on our testing CPU to find out.
Ask ten geeks about their preferred thermal interface material (TIM) and you’ll get six different answers. Five will go with Arctic Silver 5 and the others will have five totally different favorites. Ask a non-geek about their favorite thermal paste and you might get slapped.
But is Arctic Silver 5 really the best? Is the thermal testing compound we’ve been using in the lab really cutting the mustard? We gathered seventeen premium thermal pastes and an overclocked test bed and set about finding out whether thermal paste really makes a difference, and if so, which one is the best.
A Note on Methodology
Our test bed consists of an Intel Core-i7-975 CPU, overclocked to 3.9GHz. This gives an idle clock speed of 2.1GHz. Our motherboard is an Asus P6X58D Premium with 6GB of RAM and a Thermaltake Frio OCK cooler with its fans set to their highest setting, to maximize airflow. Our test bed is built into a High-Speed PC Top Deck Tech Station (large), and our PSU is an Antec TruePower 850W.
We tested each thermal paste after an hour of idling, then after three hours running Intel’s Nehalem thermal stress-testing utility at 85 percent thermal load. How’d we get that number? We applied our standard thermal testing compound—Arctic Silver Lumiére—and cranked up the utility until the CPU was consistently just under 90C, then used those settings for every future test. CPU temperatures are an average of the four CPU core temperatures as measured by HWMonitor, and we used TMonitor to make sure the processors were running under 100 percent load at their full 3.96GHz during testing.
For this test, we focused on thermal pastes that are nondestructive—none of this liquid metal stuff—and readily available in the United States.
After a few weeks of testing day in and day out, we’re ready to report our results. Here are your contenders!
The Contenders (in order of testing)
Arctic Silver Lumiére OEM Thermal Testing Compound, Price N/A (OEM only)

Arctic Silver’s OEM testing compound is a ceramic-based TIM which we’ve been using in the lab for years because of its consistent performance and lack of burn-in time. It’s not available to the general public, but we included it to see how our baseline TIM really stacks up to the competition.
Not well, it turns out. We’ve been using Lumiére since God was a kid, and it’s not bad at low temperatures, but in our stress test it pulled down temps on par with the worst performers of the bunch—89C, almost hot enough to trigger our CPU’s automatic throttling.
Geek Approved?: No

Noctua’s NT-H1 is a thick electrically non-conductive composite material that ships with the company’s CPU coolers and can also be bought separately. Noctua recommends dropping a small amount in the center of the heat spreader and allowing the pressure to spread the paste across the interface. Given the tackiness of the compound, that’s good advice.
NT-H1 is good stuff. At full burn our processor only averaged 81.25C, and at our processor’s idle temps (still far higher than most processors’ burn temps) were just 41C.
Geek Approved?: Yes

Arctic Cooling—not to be confused with Arctic Silver, which also makes thermal pastes—distributes several thermal pastes in addition to its lineup of CPU and GPU coolers and remote-controlled tugboats (yes, really). MX-4 is a non-metallic carbon-based gray compound that doesn’t conduct electricity, and Arctic Cooling says a single application will last up to eight years. It’s a bit pricy at $13 per tube, but it does the job well, with burn temperatures of just 81C and idle temps of 41C.
Geek Approved? Yes

Tuniq’s TX-4 is gray and tacky and difficult to apply even with the included spreader, which is the size of a credit card. TX-4 is not electrically conductive. Once we did get the paste applied, Tuniq TX-4 performed the best of any thermal paste in our roundup, and was the only TIM with a sub-80C score—though at 79.5C, that’s within the margin of error for our test. It’s quite expensive for the tiny amount you get per tube, so you may be just as well off with some of the less expensive pastes in the roundup, but TX-4 has top-notch performance and earns our recommendation.
Geek Approved?: Yes

ZeroTherm ZT-100 is gray, silicone-based, and easy to spread. It also comes with a finger cot, so when you spread a thin layer of it on your CPU (as per ZeroTherm installation instructions) you don’t have thermal paste on your fingertip for the rest of the day. With burn temps of 81.5C and idle temps of 41C on our test configuration, it earns our solid recommendation.
Geek Approved?: Yes

Prolimatech has a hard-won reputation as a maker of excellent, if massive, CPU coolers. It also makes PK-1, an aluminum-based thermal paste with bits of zinc oxide in it. PK-1 is gray and pretty easy to spread despite its almost claylike consistency, and doesn’t conduct electricity. It’s also one of the best thermal pastes we’ve tested, with burn temperatures under 81C and idles just over 41C. It’s cheaper than a lot of the other premium pastes, too—$13 gets you a whole 5g tube, or you can grab a 1g pouch from NewEgg for $3.50.
Geek Approved?: Yes

Rosewill’s thermal grease is cheap and easy to apply, thanks to its glorified nail-polish bottle and brush applicator, but its performance is strictly middle-of-the-road, with a burn average of 85.5C. Most of its 20g weight is the glass bottle.
Geek Approved?: No

Xigmatek’s memorably named PTI-G3606 is a silicon-based electrically non-conductive thermal grease. It’s very easy to apply a thin layer to the CPU with the included plastic spreader. In our tests it performed slightly better than the Rosewill RCX-TC090PRO, with burn temps of 84.5C.
Geek Approved?: No

Tuniq’s TX-2 is a light gray thermal paste that’s stickier than most of the ones in our roundup. It’s not conductive and it’s fairly easy to apply. In our tests it was just half a degree Celsius warmer than the TX-4, putting it within the margin of error for the tests and making it one of the best pastes we’ve tested. It’s cheaper than TX-4 and you get more in the tube, so we’d actually recommend TX-2 over TX-4 for the cheapskates.
Geek Approved?: Yes