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Noctua has returned to Computex in Taiwan with a new and improved version of its pumpless liquid cooler. This time, the company says it’s able to compete with a standard all-in-one cooler for temps.
“We had that demo last year on a 9800X3D,” Noctua’s Jakob Dellinger says, calling back to this thermosiphon prototype from 2025.
“That was roughly 100 watt heat load. This year we’re running 230 watt on a 9950X3D, and we’re neck and neck performance wise with a AIO water cooler.”
Noctua’s prototype works through evaporation. Rather than pumping hot liquid away from the CPU, the liquid heats up, evaporates, then the vapour travels up towards the radiator. In which, it condenses back to liquid and flows back down to the evaporator.
There’s a careful balancing act to get this thermosiphon principle working as intended, but Dellinger reckons they’ve got it pretty much squared away.
Noctua had the two-phase thermosiphon set-up at the show, with a 9950X3D tearing away at 230 watts—a considerable thermal load to dissipate for any cooler. The screen below noted the temperature of the chip: 81.4 °C, or thereabouts.
Next to this, Noctua’s upcoming all-in-one cooler, the NL-LC1, which is built on Asetek’s Emma V2 platform and set to launch this June. Noctua provides its top fans and a specially-designed pump cover to reduce noise with what is otherwise a traditional AIO design. The screen below this cooler noted a temperature of 79.4 °C.
Dellinger says if they dropped the pump to quiet mode on the standard AIO, the thermosiphon would come out ahead.
So, pretty close. Or neck and neck, as Dellinger would say. The thermosiphon has the benefit of no annoying pump noise, though the three fans on the radiator mean it’s not completely silent, either.
The thermosiphon design has seen a major improvement, too. What was previously very clearly a prototype unit with rough edges, the latest prototype looks pretty close to the real deal. It still comes with a bolted on fill port and it’s not quite at production level, but I’ve seen a lot worse.
“It’s a bit like Darth Vader’s mask, you don’t want to look underneath,” Dellinger jokes.
“We’re still at lab stage. The next big challenge is going to be to make sure that we can reach this performance level, not just on a prototype, but consistently in mass production.”
Dellinger explains the many improvements the company has made over the past year, which include a new microlayer to remove vapour blankets, which insulate the hot surface and reduce the cooler’s effectiveness; and tweaks to optimise the flow of liquid and vapour through the system.
It’s all about controlling the circulation and balance of liquid and vapour in the loop, Dellinger says. He also spoke in of “evaporating meniscuses”, which starts to sound a little sci-fi to me, but apparently it’s textbook knowledge for a cooling company.
I’ll drop the technical slides below if you’re interested.
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I ask Dellinger if there’s a maximum wattage that this sort if thing could deal with, and I’m told since the heat powers the system, it’s only really a question of balancing the loop for larger heat loads. At smaller sizes, things get trickier, but even air cooling with heatpipes would suffice at a lower TDP.
“We’re really focused on 360 mm, because getting good performance on 240 mm is a real challenge.”
Noctua is playing a long game here. The thermosiphon isn’t expected until at least Q3 2027, but that feels like a pretty loose estimate to me.
Noctua seems more optimistic of this prototype materialising into something real, at least. The company says it has made, “excellent progress towards performance goals and mass production.” It also says it’s gone from “from one evaporator design per month to four per day.”
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