If you’ve just splashed $2,000+ of cash on the fastest GPU on the planet, which includes one of the most impressive coolers we’ve ever seen on a graphics card, clearly the first thing you’re going to want to do is disassemble it all and water-cool it, right? Ok, so this mod might not be for everyone, but if you do want to water-cool your Nvidia GeForce RTX 5090 Founders Edition, you can rest assured that the results are worth it.
With our Nvidia GeForce RTX 5090 review proving that Nvidia‘s latest flagship is indeed the best graphics card you can buy, many might think there’s little need to try to squeeze more performance out of the card, especially as its default cooler runs relatively cool and quiet. However, that hasn’t stopped one company from seeing just what can be achieved by water-cooling Nvidia’s own RTX 5090 Founders Edition.
The company brave enough to take on this endeavor is Thermal Grizzly, a maker of all sorts of cooling equipment for CPUs and GPUs, which just last week announced an RTX 5090 graphene thermal pad. Now the company is back with its latest RTX 5090-focused potential product, which is the first water cooling block designed specifically for the RTX 5090 Founders Edition.
What makes this task so notable is that the Nvidia card not only has a remarkably good cooler already, but that it uses a flow-through design that means the card’s PCB sits in-between two fans that blow air through the card. This means that once you disassemble the cooler to get to the PCB – to put the water cooling block on the GPU – you’re left without an actual card.
Instead, the card is made up of three separate PCBs that are attached to the cooler and connected by ribbon cables. This means the water cooling block itself has to become the mounting frame on which to reattach all the parts of the original card, as shown above.
Despite all these reasons not to do it, with the FE card likely to be the most popular option among RTX 5090 buyers, the folks at Thermal Grizzly set out to prove that the task was at least possible, and prove it they did, via the company owner’s YouTube channel, der8auer, hosted by Roman “der8auer” Hartung.
With the absolutely lovely-looking solid copper block mounted to the card, and the water loop hooked up to the channel’s massive water cooling radiator and fan setup, the GPU temperature dropped from an average of 72.5°C to just 48.3°C while under full, sustained load. Meanwhile, the memory temperature also plummeted from 88.3°C to 57.7°C. The temperatures after water cooling are shown below.
These temperature drops were even more dramatic when the block was initially installed, with the GPU hitting just 24°C and the memory just 34°C. However, after 15 minutes of load testing, the water cooling loop’s liquid warmed up, resulting in the above temperatures. As der8auer points out, this setup is still pumping 530W of heating power into the water.
Not only are these numbers generally impressive but they resulted in instant performance gains too. The average GPU clock speed under load went from 2,655.1MHz to 2,679.7MHz, which is only a modest increase but this is with no extra effort whatsoever – the GPU just pushed itself to this higher speed. What’s more, der8auer thinks that overclocking “will be possible” with this cooling setup.
As for the trickiness of this mod, der8auer rates it as a solid 8.5/10 on his own modding difficulty scale, pointing out that removing some parts of the cooler is very tricky while also noting the need to heat up adhesives to remove the ribbon cables. Der8auer also notes the delicacy of the PCB that acts as the PCIe connector, with the prototype model leaving this unsupported (shown below). However, he points out that if there is a retail version of the block, this would include a support for this section, plus he also suggests the whole block wouldn’t be solid copper but partly aluminum.
Would you be tempted to take on a GPU mod like this? If you join our community Discord you can let us know your thoughts there. Or, for more on the benefits of water cooling, check out our top liquid cooler picks in our best AIO cooler guide. You can also follow us on Google News for daily PC games news, reviews, and guides.