Interview with Noctua's Jakob Dellinger

FanlessTech: Your fanless CPU cooler prototype came as a total surprise to us. It does look amazing. Passively-cooled desktop PCs are a niche market though, what type of customers are you looking for?

Jakob Dellinger: Thanks, glad to hear you like our prototype! This will be a new market for us indeed and honestly, I think for the majority of customers taking a regular forced convection based CPU cooler and letting the fans run at very slow speeds is the better option. For example, if you take an NH-D15 and set the fans to 500rpm, it will be virtually inaudible and you’ll still get very nice cooling performance. However, some customers simply prefer completely fanless systems without moving parts that are completely noiseless and have less issues with dust. Another option is semi-passive setups that have the fans off most of the time and only spin them up for short load spikes.

What price range are you shooting for?

It’s still a bit too early to tell, but we aim to stay below 100 EUR/USD.

Have you tested it horizontally?

From what we saw, convection would work just fine. Yes, it does work nicely in desktop orientation as well but you have to keep in mind that in this case, the motherboard will block natural convection a bit, so having the motherboard vertical is preferable to get the best possible results.

What are the technical challenges of using 1.5mm cooling fins? How a version featuring 1.0mm or 0.5mm fins would perform?

Our regular coolers have 0.4 to 0.5mm thick fins so going to 1.5mm is challenging because we cannot use our regular stamping, folding and interlocking machines in production. Much higher forces are required and this sort of machinery is very expensive. Reducing the thickness of the fins would have a negative impact on performance because we need a certain amount of mass in order to be able to absorb enough thermal energy.

Noctua never used 8mm heat pipes. Any specific reason behind it?

We’ve been experimenting a lot with different diameters, e.g. 7, 8 or even 10mm. The obvious advantage of larger diameters is that the capacity is higher, but there are drawbacks as well. Space is limited at the base of the cooler, so you can only fit a certain number of heatpipes in a way that is thermally efficient. For example, stacking them on top of each other or adding extra heatpipes further out to the sides wouldn’t make much sense because they wouldn’t get much thermal energy. For example, you can fit 7x 6mm but only 5x 8mm on roughly the same space, so while a single 8mm heatpipe has more capacity than a single 6mm one, the total capacity won’t be higher. Another drawback is that with less heatpipes, you can not achieve as even heat distribution across the fins as with a higher number of smaller diameter heatpipes. There’s rarely a free lunch in thermal engineering. All in all, 6mm has proven to be the sweet spot for us.

From our experience, the PC case is as crucial as the fanless CPU cooler. It must feature enough mesh for convection to occur. Would Noctua consider a list of thermally compatible chassis?

Yes, we definitely plan to have a list of recommended cases that are suitable for fanless configurations!

What about your own chassis? Will Noctua ever release a PC case?

Never say never but this isn’t something we have on the roadmap at the moment.

Over the years, Noctua showcased various prototypes that never made it to production. Will Noctua release a fanless CPU cooler in 2020 for sure?

There are still some challenges with manufacturing that we need to sort out so I cannot give any guarantee but it is our goal to have the fanless cooler out on the market next year.

Thank you so much for your time, Jakob. We just can't wait!

Images courtesy of Richard Swinburne