What is the best fanless CPU cooler? I did a direct comparison of the four most widely available fanless CPU coolers. Included were the Arctic Alpine 12 Passive, NoFan CR-80EH, SilverStone HE02, and the NoFan CR-95C. There are other coolers that will work without fans, but these are the four main coolers available today that are marketed for fanless operation. So which one is the best? Well, the main concern with fanless coolers is their ability to keep the CPU from thermally throttling. I tested the four coolers in the same system at various power levels to see how each cooler does under the same conditions. Two different CPUs were used, the Intel i5-9400 and the i9-9900. I fired up Windows 10 and ran Prime95’s torture test with small FFTs for half an hour during each run. This was done a total of 68 times, running each CPU under each cooler at 10 watt power limit intervals from 10 up to 100 watts for the coolers that could handle it. I changed CPU power limits quickly between each test so that the coolers lost as little heat as possible. This way I could get to heat saturation more quickly during each run. CPU core temperatures were tracked with HWINFO64. A total of over half a million temperature readings were recorded and processed to compile these results. The test system included an ASRock H370 Pro4 motherboard installed in a Fractal Design Meshify C case. The case was stripped down, all fans, drive bays, and dust filters removed for optimal natural passive airflow. With that, let’s get to the thermal results before looking at a broader comparison of the four coolers.
Below are the results for the Arctic Alpine 12. These results are an average of the readings from the i5 and i9 processors. This cooler is marketed as a 35 watt TDP cooler. Keep in mind that TDP is a very loosely defined parameter, and that a CPU’s TDP is not a good indicator of its actual power use. The y axis here is Celsius above ambient. The ambient room temperature was subtracted from the average core temperature for each minute the tests were run. The Alpine 12 passed the 60 watt tests without any throttling, and began throttling during the 70 watt tests. You can see here that the maximum temperatures increased by an average of about 10 degrees each time the power limits were increased by 10 watts, 10.4 degrees to be exact.
These are the results for the NoFan CR-80EH. The CR-80 passed the 80 watt tests, but failed during the 90 watt tests. Maximum temperatures increased an average of 7.6 degrees for every 10 watts of power use.
The SilverStone HE02 passed even the 100 watt tests. When I tried 110 watts, the VRMs began to throttle the power back, so my tests ended at 100 watts. Maximum temperatures with the HE02 increased an average of 5.7 degrees for every 10 watts of power use.
Finally, below are the NoFan CR-95C results. Maximum temperatures increased an average of 5.0 degrees for every 10 watts of power use. The maximum temperatures have gone down each time the cooler was changed; the NoFan CR-95 did the best, the SilverStone HE02 did second best, the NoFan CR-80 third, and the Arctic Alpine 12 last.
Below is a summary of results for the Intel i5-9400 and i9-9900. Results between the HE02 and CR-95 are pretty close, but there are big gaps between the Alpine 12 and CR-80 and between the CR-80 and the HE02. We get a good look at how the coolers do with Intel CPUs that have soldered heat spreaders like the i5 and i9 tested here. AMD Ryzen results should be comparable, but be aware that 9th generation Intel i3 CPUs have thermal paste below the heat spreader or IHS, and will have worse results. Linear trendlines were added to the data, and formulas for stressed core temperatures were determined. If we use these formulas to calculate the theoretical maximum CPU power uses for each cooler, assuming an ambient room temperature of 25 degrees Celsius and maximum core temperatures of 100 degrees, we get 58 watts for the Arctic Alpine 12, 81 watts for the NoFan CR-80EH, 113 watts for the SilverStone HE02, and 126 watts for the NoFan CR-95C. These results are about as good as can be, and results will vary with difference processors, different motherboards, and with different PC cases.
Let’s look now at a broader comparison of these coolers. All of the coolers except for the NoFan CR-95C are compatible with modern Intel and AMD processors, although the AM4 compatible Arctic cooler is a slightly different model, known as the Arctic AM4 Passive cooler, but it is more or less the same. The NoFan CR-95C is not compatible with AMD AM4 processors out of the box, but it can be modified if you are comfortable with a ruler and a drill to be made compatible with AM4 processors. The cooler heights are listed here, which is important when choosing a case for one of these coolers. The SilverStone HE02 is the tallest at 160 mm. The weights are listed just below that. The HE02 is also the heaviest, at 990 grams. If aesthetics are important, the coolers come in a variety of colors; black for the Alpine 12, copper for the CR-80, silver for the HE02, and either copper or silver for the CR-95. Ease of installation may also be a concern. The Alpine 12 is the easiest. It is simply a cut piece of aluminum with four screws. The CR-80 is a little more complex, with two brackets that need to be attached to the cooler before installation. The HE02 is the most difficult to install. It has a more elaborate mounting mechanism, and requires a long screwdriver and a good amount of patience to get mounted properly. The CR-95 has a simpler design, with four mounting holes and four mounting screws. Price is obviously another important consideration. The Arctic Alpine 12 is the best value at just $16 including shipping, although it is best used if you are willing to limit power settings in BIOS, which also limits performance. For full performance, the SilverStone HE02 is the best value option at $68. The NoFan coolers are more expensive for the performance they offer, but are still great options, the CR-95 being the best performer of the four. It is about twice the price of the HE02 however, so it may only be for the silent PC enthusiasts.
I included some other notes here for consideration. The Alpine 12 does have any notes since it is widely available and has no compatibility issues. The CR-80 is sometimes out of stock, so its prices fluctuate widely depending on when you look for it. The HE02 is large and won’t fit in all cases, but a benefit it has is that it is asymmetrical and can be rotated for optimal combability with various memory, PCIe slot, and CPU socket locations. The CR-95C has been discontinued, but is still available from QuietPC USA or from Fully Silent PCs, while supplies last. It is large enough that it will block one or two PCIe slots, depending on the motherboard, and it is not compatible with Mini ITX motherboards because it would hang over the input/output side of the motherboard and interfere with the PC case.
So, if you were considering a fanless CPU cooler to quiet a more standard tower style PC system, I hope this guide has been useful. Keep in mind that the case chosen and room temperature will have a significant effect on CPU temperatures. An alternative to these CPU coolers include integrated heatsink-cases such as those from Streacom, HDPlex, and Akasa. You can find a wide variety of custom built fanless PCs at fullysilentpcs.com.