My heart is aching for this tiny single slot RTX 4090

Oh boy, I thought the RTX 4090 Founders Edition looked good, but this is like my fantasy RTX 4090 design. This is like a single slot version of Nvidia's top GPU—hell, the world's top GPU right now—yet it channels the utilitarian chic of my all-time favourite graphics card, the GeForce 8800 GT. 

And is unfeasibly even smaller.

But this is not a graphics card that you can go out, pull off the shelf, stick under your jumper, and take home to your rig. No, this is what happens if you mix a third-party RTX 4090 with Alphacool's Enterprise Series water block. And, oh my, does it have my attention.

Optimum Tech has picked up the block and installed it on an Inno3D card—the iChill X3 to be precise—and notes that there are actually only a few cards' PCBs that do actually fit the Alphacool block. There are a few specific Inno3D models, but the block maker's site does state that while it's not compatible with the Nvidia Founders Edition, it is compatible with any card built using the standard reference design PCB Nvidia supplied to its partners.

As an ES block it's designed to go into server racks, hence the single slot design, lack of RGB bling, and the fact the hose connections are located at the rear. 

But that is by no means a bad thing, because just look at that sleek wee hunk of metal. This is all made possible by the fact that the actual PCB (printed circuit board) for Nvidia's RTX 4090 is actually very small. The Founders Edition and AIB cards all look absolutely monstrous because of the level of cooling necessary to keep this 450W AD102 chip under control.

When dropped into a decent liquid cooling loop, however, there is enough chip chilling on offer to keep the RTX 4090 running cool and practically silent. Optimum Tech demonstrates the card in action on an open test bench, with a single radiator cooling both GPU and processor, and the temperatures look great.

Optimum Tech video showcasing the RTX 4090 water block from Alphacool

(Image credit: Optimum Tech)

They note it's within a few degrees of a water-cooled RTX 3090 and around the same as MSI's hybrid water cooled RTX 4090 Suprim-X, which is a great result. As is the 56°C average noted when stressing the chip via the fluffy power virus, Furmark. Running a few games—God of War and Control—the temps remain around the same level, if a little lower, and the card's still able to post 2.7GHz+ clock speeds.

That's the same sort of speed as our massive RTX 4090 Founders Edition, which I'm now looking at with disgust. Bloated sack of GPU that it is.

Of course, these water blocks don't come cheap. The Alphacool ES is retailing for $166 and EKWB has a similar one (that's a little larger) as part of its own enterprise range and that's around $250+.

But hell, if you're going to spend $1,600 or more on a graphics card, what's another couple hundred dollars to make it look like an absolute legend? 


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Dave James
Managing Editor, Hardware

Dave has been gaming since the days of Zaxxon and Lady Bug on the Colecovision, and code books for the Commodore Vic 20 (Death Race 2000!). He built his first gaming PC at the tender age of 16, and finally finished bug-fixing the Cyrix-based system around a year later. When he dropped it out of the window. He first started writing for Official PlayStation Magazine and Xbox World many decades ago, then moved onto PC Format full-time, then PC Gamer, TechRadar, and T3 among others. Now he's back, writing about the nightmarish graphics card market, CPUs with more cores than sense, gaming laptops hotter than the sun, and SSDs more capacious than a Cybertruck.