Steam Deck prototype has half the gaming performance of the retail unit

A rare engineering sample and prototype version of what would become the Valve Steam Deck has been disassembled and tested in a fascinating new video.

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Kosta Andreadis

Senior Editor

Published Jun 16, 2025 2:01 AM CDT

2-minute read time

TL;DR: Valve's early Steam Deck prototype, "Engineering Sample 34," features a distinct design, a Ryzen 7 3700U APU, and a 720p display, differing from the retail model's custom Zen 2 APU and 800p screen. This proof-of-concept highlights Valve's multi-year development and hardware evolution before the final release.

Earlier this year, we reported on "Engineering Sample 34," an early Steam Deck prototype from Valve that sold on eBay for $2000 ($1000 less than the asking price of $3000). As seen in pictures, the prototype handheld features a different design than the retail unit with blue-colored buttons, more curves, and circular trackpads.

Hands-on with prototype Steam Deck "Engineering Sample 34," image credit: YouTube/Bringus Studios.

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The buyer, SadlyItsBradley, loaned the rare piece of Valve hardware history to tech YouTube channel Bringus Studios for a deep dive into the hardware. That video is now online (you can watch it in full below), and it's a fascinating look at a very early version of what would become the Steam Deck.

The hardware inside has a late 2019 production date stamped on it, which suggests that it is more of a proof-of-concept device than a functional gaming handheld. In the video, we discover that the 'Picasso APU' is a Ryzen 7 3700U with integrated Radeon Vega 10 graphics, which is far less powerful than the custom Zen 2 APU with RDNA 2 graphics on the retail model.

Read more: Early Steam Deck prototype was sold on sold on eBay for $2000

Inside prototype Steam Deck "Engineering Sample 34," image credit: YouTube/Bringus Studios.

After several stops and starts and discovering that the handheld had a very early version of Valve's Linux-based SteamOS on it (the build dates back to September 2020), Bringus Studios was able to get a few games like Counter-Strike 2, Lego Star Wars: The Skywalker Saga, and even Cyberpunk 2077 running; however, the performance was unplayable. This can be attributed to a lack of official drivers and optimizations.

Interestingly, the Steam Deck's "Engineering Sample 34" is almost the same overall size as the retail unit, with similar button placement. It shows us that Valve spent several years working on the Steam Deck, ultimately landing on the version we see today. Other interesting differences include the prototype featuring a 720p display, like the Nintendo Switch, which evolved into an 800p display on the final retail release. Also, the analogue sticks were smaller and more like the "mobile" quality sticks of the Switch as opposed to the full-sized versions on the retail unit.