This tiny water-cooled RTX 4090 can fit in the smallest ITX build

Have you seen the stonking great size of the latest high-powered cards from Nvidia and AMD? Three-plus PCI slot-thick designs seems to be the new standard for anything above the midrange. That’s making it harder and harder to find a new, high-end card that can fit in those adorable mini-ITX PC builds. If you’re breaking rulers in frustration, you might want to check out a new custom watercooling block that makes the RTX 4090 small enough to fit into a single slot.

The block was discovered by YouTube channel Optimum Tech (via PCGamer) and featured in a recent video. The Alphacool ES block is just 209 millimeters long and 24 millimeters thick, a bit thicker with the GPU’s PCB actually installed. And on that note, not just any old RTX 4090 will do: this block is only compatible with a handful of cards from Inno3D, plus the reference design (not the Nvidia Founder’s Edition). It’s designed for enterprise applications, so it has no flashy RGB or other embellishments.

If you can find the right card, you still need a liquid cooling setup with a custom loop powerful enough to handle it while working with the rather small coolant line fittings. But if you’re down for all that, installing the block probably won’t phase you, and neither will the $166.36 part cost. Once everything is set up, the result is a card that’s approximately one-quarter the volume of the stock RTX 4090 and ready to fit into pretty much any water-cooled PC.

Optimum Tech found that the water-cooled RTX 4090 didn’t take any huge hit in thermal performance on his test bench. While you won’t get the full cooling power that a larger setup can deliver, it’s more than enough to run the latest games and make them look their best. And if you’re trying to build a screaming fast gaming PC with the latest parts in a mini-ITX case, it might be your best option.