Steam Deck: what sort of gaming performance can we expect from Valve’s handheld PC?

Valve Steam Deck on a green and purple gradient background

(Image credit: Future)

It’s been less than 24 hours since Valve announced the Steam Deck, but what a busy period it has been. The PC gaming handheld has made quite a splash online and has already worked its magic on some members of the team as they look to ditch their Nintendo Switch. But the first question on my mind when I heard Valve’s portable plan was in regards to tech specs: What is going on under the hood to make this happen? So with that in mind, let’s dive into the Steam Deck’s silicon heart to see what’s going on and how it might compare to today’s components.

What powers the Steam Deck hasn’t been ripped directly out of Gabe Newell’s imagination. Instead, it’s built by a company that’s, say, a little well-known in the gaming industry today: AMD.

AMD has an extremely successful semi-custom unit. What that means is it produces components for other companies for use in their own products, and it will work with said companies to get those parts up to spec and operating as intended. AMD is the chip designer behind both the Xbox Series X/S and PlayStation 5, as well as their immediate predecessors, so it has a deep understanding of creating chips for this purpose.

Valve says it partnered closely with AMD on the Steam Deck’s new accelerated processing unit (APU), to get it running as Valve requires. We still don’t know the full extent of this partnership, however.

What we do know is that AMD was previously rumoured to have an altogether similar APU in the works by the codename ‘Van Gogh’. This chip is now an exact fit for the specifications announced for the Steam Deck.

AMD's CEO Lisa Su at CES 2020

AMD’s CEO Dr. Lisa Su holding a mobile APU with Radeon GPU and Zen 2 Ryzen Threadripper processor. (Image credit: AMD)

So it could be that Valve saw what AMD could offer in its prospective Van Gogh chip and decided it was a good fit for the Steam Deck. Either that or the two companies could have worked more closely to refit or design such a chip purely for this device.

Either way, what matters are the specifications of that APU. So let’s get into the tech specs.

The Steam Deck APU uses AMD’s Zen 2 CPU architecture and RDNA 2 GPU architecture. What this means is that the processor component is similar to AMD Ryzen 3000-series processors on desktop, while the GPU component is a match for the Radeon RX 6000-series graphics architecture.

We do have to be a little careful with such comparisons, however. There are no chips which are the exact mirror-image of the one found in the Steam Deck today, and desktop counterparts, such as the Radeon RX 6700 XT graphics card, have many more cores inside them than the Steam Deck can offer. Similarly, the Xbox Series X/S and PS5 utilise the exact same CPU and GPU architecture, although once again are far from a match numbers-wise.

There’s no direct apples to apples comparison, essentially.

(Image credit: Valve)
Steam Deck specs
Steam Deck
Core count 4-core/8-thread
CPU clock speed 2.4–3.5GHz
GPU Compute Units 8
GPU clock speed 1–1.6GHz
RAM 16GB LPDDR5 @ 5,500MT/s
Storage 64GB eMMC / 256GB NVMe SSD / 512GB NVMe SSD
Display 7-inch LCD touchscreen
Resolution 1280 x 800
Refresh rate 60Hz
Audio Stereo speakers, 3.5mm jack, dual mics, USB Type-C/Bluetooth
Connectivity Wi-Fi, Bluetooth, USB Type-C with DisplayPort 1.4 support
Battery 40Whr
Size 11.7 x 4.6 x 1.8-inch (298 x 117 x 49mm)
Weight Approximately 1.47 lbs (669 grams)
Price $399 (64GB) / $529 (256GB) / $649 (512GB)

Onwards to the specs, though, and the Steam Deck features a four-core/eight-thread Zen 2 CPU. That’s roughly equivalent to the Ryzen 3 3100 CPU, although the Steam Deck CPU runs a touch slower at 2.4-3.5GHz. That’s likely a move to keep this chip within a fairly restrictive power envelope, thus extending battery life and minimising thermal demand—the whole AMD APU in the Steam Deck requires just 4-15W of power.

Then there’s the GPU component; the main driver for the gaming experience on the handheld. This is formed by eight RDNA 2 Compute Units (CUs), making for 512 cores in total. The RDNA 2 architecture means each of these CUs will be accompanied by an RT Core, which will nominally allow for ray tracing acceleration. However, such a slim number really won’t make for a great experience in any ray-traced game.

This RDNA 2 GPU will run at 1–1.6GHz and deliver up to 1.6 TFlops FP32 performance. That is a general marker of this chip’s compute performance, but again isn’t entirely comparable with older or competing GPU generations. It’s more of a guideline, let’s say.

Never mind performance, what’s it going to be like to game with these tiny trackpads? (Image credit: Valve)

Connecting all that silicon together is 16GB of LPDDR5 RAM at 5,500MT/s. This new memory standard is quick by even today’s standards, and outpaces most DDR4 memory found in modern gaming PCs. While DDR5 will offer an even greater leap in performance, the lower-power mobile LPDDR5 memory still offers tremendous speeds.

Valve’s offering a happy blend of speed and capacity that the Steam Deck will likely need to offer a solid gaming experience. That LPDDR5 memory is a bit of a wildcard, though. It’s fast and there’s plenty of it, but it’s also going to be divided between CPU and GPU and cannot offer the bandwidth that graphics-specific GDDR6 memory can, which you’d find on any modern discrete graphics card in laptop or desktop. Or, perhaps more importantly, in any console running a similar APU.

We’d guess it will be up to scratch for small-screen gaming in the Steam Deck’s handheld mode, but I’d be cautious to suggest it will outpace many fairly modern gaming PCs with a discrete GPU.

We’d also be cautious about Valve’s ambitious statement regarding the Deck that “with a custom processor developed in cooperation with AMD, Steam Deck is comparable to a gaming laptop with the ability to run the latest AAA games.”

(Image credit: Valve)

What sort of gaming performance can I expect from the Steam Deck?

With the general specifications in hand, we can at least begin to extrapolate rough performance figures for Valve’s new device—bearing in mind everything I just said about this not being a perfect science.

In terms of TFlops, the RDNA 2 chip within the Steam Deck is a match for Intel’s 96 EU Xe graphics, which is most commonly found within Intel Tiger Lake mobile processors. Intel’s GPU offers between 1.7 and 2.1 TFlops of FP32 performance, so a touch higher than the RDNA 2 chip in the Steam Deck, but it’s worth mentioning that the RDNA 2 architecture is built first and foremost for gaming and has shown itself plenty capable of more than making up for raw compute power when it comes to frame rates.

If you’re happy to run your games on low to medium settings at 720p to hit 30 – 60 fps, then the Deck should deliver.

Lucky for us, we’ve not only tested Intel Tiger Lake’s 96 EU iGPU, our own Alan Dexter has taken said GPU for a spin in another PC gaming handheld, the One-netbook Onexplayer. 

The Onexplayer also comes with a four-core CPU with up to eight threads, 16GB of albeit slower DDR4 RAM, and that 96 EU Intel Xe GPU. So it’s as good a match-up as we’re going to get.

The Onexplayer manages to offer 35fps in Shadow of the Tomb Raider at 720p and with low graphics settings enabled. In GTA V, that increases up to 60fps, which isn’t too bad at all. Alan reports further success in games such as Dirt Rally, Forza Horizon 4, and low-impact games such as Hearthstone or MtG Arena.

Cyberpunk 2077 was, of course, out of the question.

One issue Alan notes in his Onexplayer review might also be something we encounter with the Steam Deck, and that’s getting games to run at the native 1280 x 800 resolution, or 16:10 aspect ratio. It’s far more likely for games to support a 16:9 720p resolution, and you may find games run that little bit better at that size, too.

So that’s a general idea of performance. More nebulous concepts of performance would say this is roughly equivalent to the PS4 or Xbox One, although that’s a slightly more difficult comparison as console games don’t often offer frame rate counters and the like. In terms of raw CU count, the Steam Deck is just under half the specification of the Xbox Series S, although, again, there are all sorts of memory and other architectural changes you’d need to consider to say anything of value there.

That’s a bit of a dive into what to expect performance-wise from the Steam Deck, anyways. Not quite the “powerhouse” Valve claims it to be,  but if you’re happy to run your games on low to medium settings at 720p to hit 30 – 60 fps, then the Deck should deliver. But that’s not the whole picture, and we’ll likely have to wait until we’re closer to the Steam Deck’s release date in December to find out more.

After all, it’s important to set expectations for a device such as this. Is it going to crush in the latest games? No. Is it going to drive the Valve Index in VR? No. Is it potentially a great way to play PC games in bed or on the train? Hell yeah, it looks like it. 

If you are tired of feeling stuck to your desk, this is one way to escape—at least while the 40Whr battery lasts.

There’s no ‘Silicon Valley’ where Jacob grew up, but part of his home country is known as ‘The Valleys’ and can therefore be easily confused for a happening place in the tech world. From there he graduated to professionally break things and then write about it for cash in the city of Bath, UK.

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