A SteamDeck with a fixed PC graphics card, what does it give?

The first customers started receiving their Steam Decks a few weeks ago. And knowing Valve’s very open policy, which considers that everyone can do what they want with their machine and does not intend to lock any possibility, we were already expecting a real idyll between modders and Valve’s hybrid PC.

The most impressive of these early proposals comes to us from YouTuber ETA Prime; to further boost the capabilities of its Steam Deck, it simply grafted it… a dedicated graphics card for desktops.

Remember that if Valve has guaranteed a certain degree of openness for its machine, the possibility of adding an eGPU was not really one of the priorities; the Steam Deck is absolutely not designed to work with any additional graphics card. But it takes more to stop this veritable Dr. Frankenstein of hardware.

A Steam Deck with a Radeon RX 6900 XT

The Steam Deck does not offer an additional dedicated PCIe socket? Never mind, just go through a back door! Indeed, the most expensive versions of the Steam Deck also have an M.2 slot to connect their SSD. And this one is precisely based… on the PCIe bus! Some sorcerer’s apprentices have therefore suggested that it would be possible to plug in a GPU.

And the ETA Prime videographer did not go easy on it. He set his sights on a Radeon RX 6900XT. It is a high-end graphics card whose most direct competitor is Nvidia’s RTX 3080. Suffice to say that it is a particularly powerful plugin.

And against all odds, it worked! The Youtuber claims that his modified Steam Deck is capable of running games in 4K in Ultra at framerates worthy of fixed machines at the forefront of current configurations. The experience must be quite impressive, but is it worth it?

False good idea or interesting lead?

In a word : Nope. It’s a very interesting engineering experience, but the setbacks outweigh the upside. The first of these is strictly logistical. It will not have escaped your notice, the Radeon RX 6900 XT is much larger than the Steam Deck itself. No chance, therefore, of being able to insert it inside, let alone close it.

Result: the Steam Deck turns into a fixed console with a ridiculously small screen… and with a GPU placed next to it, as discreet as an elephant in a corridor, and just waiting to blow your lungs during the game. . The icing on the cake: the Steam Deck is absolutely not designed to power this type of hardware. It will therefore be necessary to add a dedicated power supply…

To put the final nails in the coffin of this wacky idea, the Youtubeur also explains that Nvidia GPUs do not work for this use. Also, even with an AMD card, performance will be limited. Indeed, the architecture of the Steam Deck has a big bottleneck; she does not allow the card to leverage more than 4 PCIe laneswhich is not much for a GPU of this caliber.

Moral of the story: the experiment was doomed to failure… but we can still draw some lessons from it. Starting with the fact that the Steam Deck is not fundamentally incompatible with a dedicated graphics card. Will this be enough for Valve to add a real next-gen eGPU support? The future will tell us, but there may be something to dig on that side!