Noctua’s Massive, Passive CPU Cooler Is Shipping Soon
Back in 2019, Noctua created something of a stir when it showcased a CPU cooler capable of dissipating the 95W TDP of a Core i9-9900K without requiring a fan. A large amount of interest in the passive cooler showed there was a market for the concept, and the company is now teasing the product’s imminent launch on Twitter:
Coming very soon! 😉
— Noctua (@Noctua_at) May 16, 2021
Noctua has previously claimed that this 3.3-pound (1.5-kilogram) cooler can cool a 120W CPU inside a closed chassis with no fans or a 180W CPU if the system has some degree of internal cooling. We don’t have any details on the socket mounting system yet, though the company shared a teaser image close-up.
It’s not surprising to see a market for this kind of product. Quiet and silent PC build guides were quite popular in the 2000s, probably because high-end enthusiast coolers of the era were more likely to use obnoxiously loud fans than the typical high-end air cooler of today. Fanless PCs were always a bit more niche, but they had their fans adherents until CPU power consumption rose high enough to mostly push the concept out of the market. You can still buy a fanless PC today, but it’s not going to feature a high-end CPU.
Noctua is one of the best cooler manufacturers in the business — I’ve always been a fan of how the company designs and documents its products — so I don’t doubt that this CPU cooler works. Anyone interested in buying it, however, needs to also be comfortable adjusting power management options in UEFI or via AMD’s Ryzen Master, depending on your platform and CPU vendor.
Current Intel desktop CPUs do not limit themselves to the TDPs specified on the box unless ordered to do so via UEFI power management adjustments. Typically, motherboard vendors allow CPUs to run at more aggressive clock and power targets, with the result that high-end Intel desktop CPUs can draw more than 250W. No passive CPU cooler can really handle this.
AMD users have the option to use Ryzen Master to activate Eco mode and automatically limit their CPU to the next-lower TDP bracket. This can be further tweaked on some motherboards; I’ve tested dropping the TDP on a Ryzen 9 5950X all the way down to 45W on a TUF-Gaming B550 Plus.
Conventional high-end CPU turbo modes may not play well with passive coolers if you also plan to run the chip under a continuous workload. Turbo modes assume a continuous flow of air across the heatsink and that the heat from any given workload and frequency can be dissipated away quickly as soon as the chip drops back to idle. A completely passive cooler cannot quickly dissipate away the additional heat dumped into it when a CPU goes from a nominal 95W TDP to a 140-180W peak power draw. Rocket Lake is capable of drawing even more. Any passive cooler could wind up struggling in these situations.
We expect many CPUs to handle Turbo well, especially chips with lower maximum power consumption, but if you plan to push the envelope with sustained workloads running on something in the Core i7 / Core i9 family, it may be worth experimenting with both undervolting and non-turbo clocks to see which combination of settings offers the best overall performance.
Anyone considering a silent PC or fan-free PC needs to remember that fan-free does not automatically mean dust-free. Dust is a great insulator and it will impact the cooling performance of any CPU heatsink over the long term, including a fanless one.
Feature image credit: Richard Swinburne