What's inside the Piston Steam Box prototype?

Digital Foundry on what to expect from the Valve-funded mini games machine

Steam Box is real. Valve is intent on making a series of x86-based living room PCs and prototypes are present at CES 2013. Based on PC architecture and running Linux, the Piston concept from manufacturer Xi3 is an ultra-tiny metallic cube that boasts an impressive array of PC inputs and outputs and is said to draw just 40 watts from the mains - half that of an Xbox 360. It's understood that Valve itself has invested in Xi3 and that the kit is present - along with other designs - in its CES booth.

"In its current form, Piston looks like a niche device designed with form factor - rather than gaming performance - in mind."

"Today marks the beginning of a new era for Xi3," says Xi3 CEO Jason A. Sullivan. "This new development-stage product will allow users to take full-advantage of their large high-definition TV displays for an amazing computer game experience. As a result, this new system could provide access to thousands of gaming titles through an integrated system that exceeds the capabilities of leading game consoles, but can fit in the palm of your hand."

Whether this is actually going to make it to production remains to be seen, and we note the careful use of "could provide" rather than "provides" or "will provide" in Sullivan's quote.

Essentially, what we are looking at here is laptop technology sans screen and keyboard, refactored into an upgradable, modular and very, very small piece of kit. Inside the svelte cube exterior we find a rather innovative approach to PC design in that the motherboard is divided into three distinct sections arranged into a U-shape. At the bottom we find the processor control circuit board which houses the APU and RAM, flanked by two IO boards. The beauty of the design is that all three of these boards can be swapped out for other options, or upgraded. The downside is that three different mainboards are likely to cost significantly more to manufacture than a single product.

It's the processor board itself that is the most interesting element. Shots of the interior have previously shown what looks remarkably like a desktop AMD CPU nestling at its core, but the specs for the "performance" X7A model on which the Piston is based are a complete match in every respect for the mobile Trinity APU released in laptops this year, and reviewed by Digital Foundry's Tom Morgan. AMD's APUs are essentially power-efficient multi-core processors backed by integrated graphics cores that offer the same kind of performance you'd find from an entry-level GPU. Previously regarded as something of a joke, IGPs are now being taken seriously by both Intel and AMD, with the former making significant strides with its HD4000, though AMD's offerings are well ahead when it comes to gaming performance.

"The miniscule dimensions of the Piston limit the kind of rendering power available. The device almost certainly uses a mobile version of AMD's Fusion technology."

So with 384 shader cores and a quad-core CPU that boosts up to 3.2GHz, we're essentially looking at something very much like the top-end mobile AMD Trinity core, a piece of technology we've put through its paces on the most demanding of games. Dotted throughout this article you'll see how it copes with the likes of Battlefield 3, Crysis 2 and Skyrim, but the bottom line is that there is no "next-gen" performance here - at 720p resolution, we see some improvement on the DICE classic compared to the Xbox 360 and PlayStation 3, while the results with the Crytek and Bethesda epics are somewhat inconclusive. We also need to factor in that BF3 and Crysis 2 are running at low quality settings, though we can invoke the high profile on Skyrim and still get acceptable performance. However, in all cases, we're looking at an approximate 720p30 and so we're firmly in current-gen console territory.

In a year which will be defined by the next-gen offerings from Sony and Microsoft, this places the Piston in rather a strange situation - it represents the "consolification" of a platform which is traditionally associated with massive performance gains over the dedicated games machines, but is looking decidedly sub-par compared to the hardware that is to come. Instead unique appeal lies into its ultra-tiny form factor.

Above: Battlefield 3 running on the AMD Fusion APU almost certainly to be found in the X7A device from Xi3 on which the Piston prototype is based. The chip runs the game at low settings at around 720p30 with v-sync engaged.

However, while interesting from a broad ballpark performance aspect, what we are looking at here is Windows performance, and Valve will be running Linux. NVIDIA's Timothy Lottes (creator of FXAA and TXAA) makes some compelling arguments on his blog for the advantages that the open-source OS and OpenGL have over Windows, and it's well known that Valve has a crack team looking into gaming optimisations for the platform as well as developing tools and workflows to make porting games across simpler and easier than it is now. A point which really stands out in Lottes' comments is the fact that when a game is running on Linux it has access to the capabilities of the whole machine with no background processes eating away at performance.

"While we expect significant improvement in this year's revisions, the current-gen AMD APUs offer ballpark gaming performance with Xbox 360 and PS3."

While many won't be too impressed with a new hardware proposition that offers little in the way of a generational boost in gaming visuals over the seven-year-old Xbox 360, one factor that needs to be stressed is that the X7A hardware on which Piston is based is a modular system that can be upgraded - and that the new hardware has no definitive, locked-down specs. AMD's desktop Trinity platform (essentially identical to the notebook version, albeit with higher clock speeds) is based around a CPU socket that has been designed to be future-proof for several years, and it wouldn't surprise us at all if the same thing were true of the mobile equivalent. That being the case, it may well be that the production Piston uses the upcoming revision of the Fusion APU, which should see redesigned, more efficient CPU cores working in concert with a GPU upgrade derived from the hugely successful GCN architecture that powers all of AMD's 7xxx graphics cards. There will also be a shared memory space accessible by both the CPU and GPU elements of the processor.

In short, we could expect to see a significant bump over the performance seen with the current Trinity APU, but factoring in the tiny form factor of the unit and the low power draw inherent in the design, it's probably still going to fall some way short from what we can expect from the next-generation consoles from Sony and Microsoft, which we expect to guzzle power in comparison. Indeed, the chances are that there'll be considerably more powerful Steam Boxes out there, including the "prime" reference design box from Valve itself.

Above: Even on the lowest detail settings, we struggled to get Crysis 2 running smoothly on the AMD Trinity laptop and needed to run at 1024x600 to get something approaching a locked 30FPS.

The direction taken with the Piston concept has drawn some sharp criticism from hardcore gamers, perhaps hoping for a Steam Box more along the lines of the Alienware X51, which these days features the latest Ivy Bridge CPUs in combination with the Nvidia GTX 660, providing a gaming experience considerably beyond current-gen consoles. Not helping matters is the fact that the price-point for the Xi3 weighs in at a wallet-worrying $999 - ballpark X51 money. Built in bulk, it's clear that this relatively simple design could be sold for a much lower price, so the real question in determining cost is how much AMD would charge for the APU: retail cost of the desktop Trinity chip is around £93 while complete laptops built around the A10-4600M aren't exactly cheap either. Any prospective Steam Box manufacturer is going to come up against the same hurdle - relatively speaking, off-the-shelf silicon isn't cheap unless you have the buying power of Dell or HP behind you.

"While Piston may address a high-end niche, we expect Valve's own box to offer a superior price to performance ratio, similar to our own Digital Foundry PC."

Of course, the fact that the Xi3 has received Valve funding and that the Piston is an element of the firm's CES booth doesn't necessarily mean that this is the Steam Box - we still expect to see a unit with a more gamer-friendly performance to price ratio. Gabe Newell has made it clear that it is just one of a number of prospective models, and there's a chance that Xi3's model may never actually come to market at all in its current form. Perhaps it's no surprise then that Valve's Doug Lombardi has also sought to contain the Piston story. While not denying the Valve connection, the prototype doesn't even warrant a mention in his comments to the press. "Valve will be at CES to meet with hardware and content developers in our booth space," he told Polygon. "We are bringing multiple custom (hardware) prototypes as well as some off-the-shelf PCs to our CES meetings." Lombardi clarified those designs, describing them as "low-cost, high-performance designs for the living room that are great candidates for Steam and Big Picture".

With the power of the Steam brand behind it though, it's safe to say that Valve will have many suitors looking to provide hardware, and the whole point of embracing Linux in the first place is to create the open platform that Gabe Newell and his colleagues believe is in jeopardy with the release of Windows 8. It's going to be very interesting to see how all this develops...

Above: Skyrim could run at 720p on high quality settings on the AMD Trinity APU with FXAA engaged, but frame-rate struggles in places.

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Latest comments (10)

James Prendergast Process Specialist 9 years ago
"but is looking decidedly sub-par compared to the hardware that is to come."

So we know for sure what is coming? There have been press releases etc? I think even with insider information this is a little bit of a pull-from-the-hat remark. The trinity APU may not be the best out there but it's way better than the tech in either the PS3 or the Xbox 360. Just remove the OS overhead and trim it down and you'd get better performance than the console versions you're erroneously comparing it to in this article. It's a completely "apples to oranges" situation.

With regards to the linux comments, there's also no reason why MS couldn't release a pared-down gaming OS akin to how their console/server/media centre/tablet/whatever OS-specific iterations are handled (though they won't). There are also huge problems with a lot of games not running nicely on Linux unless you're using an emulation environment like WINE... but then, running WINE is quite a large background process, isn't it?

Overall, for me personally, the Steambox is a curio - an oddity that may have some application depending on its specific implementation but might look pointless when PC gamers already have the ability to network the output of their boxes to their TVs and wireless controllers allow playing on the couch.

Edited 1 times. Last edit by James Prendergast on 9th January 2013 1:12pm

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Tom Keresztes Programmer 9 years ago
With regards to the linux comments, there's also no reason why MS couldn't release a pared-down gaming OS akin to how their console/server/media centre/tablet/whatever OS-specific iterations are handled (though they won't).
I doubt they will. Microsoft would have released a more configurable pro version of Windows which would make it more suitable, but choice is not on their feature list.
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James Prendergast Process Specialist 9 years ago
I agree completely - which is why I wrote so :p - and I also think cannibalising their Xbox ecosystem is a pretty huge disincentive as well!
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Show all comments (10)
The piston size and form factor is sexy.

The price is definitely not. Ironically its size works against it here. we expect smaller devices generally to be cheaper, not more expensive.

The Linux wrinkle surprises me. Even with Epic backing a Linux play, this will be a hard sell to gamers who want access to the full range of available titles. At $100 it might have a shot as a new kind of console, at almost $1000 i think its a non-starter
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James Hoysa , Waggware9 years ago
Can't USB devices be plugged into each other or a hub? 8 USB ports seems like overkill.
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Craig Bamford Journalist 9 years ago
That's the whole reason this is even happening, I think. MS seems to have made it pretty clear that they aren't terribly interested in PC gaming. It doesn't offer the kinds of royalty revenues that their consoles do, doesn't help them loosen Apple's viselike grip on tablet gaming, and doesn't get their products on people's televisions. They need the Xbox ecosystem badly, whereas the open PC gaming platform isn't much more to them than a headache.

Makes sense that Gabe would see this and start taking steps. Maybe the Piston ain't it, but it shows where they're going.
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Most USB devices don't have a diasy chain port.

Additionally, it depends on how they are wired internally. Daisy chaining adds latency. If each of those 8 USB ports has its own hardware serial line they will operate faster.

Edited 1 times. Last edit by Jeffrey Kesselman on 9th January 2013 6:34pm

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Paul Johnson Managing Director / Lead code monkey, Rubicon Development9 years ago
"...and the whole point of embracing Linux in the first place is to create the open platform that Gabe Newell and his colleagues believe is in jeopardy with the release of Windows 8"

Oh come on, does your spin detector not work at all? The point of going with Linux is that it doesn't have a big license fee. End.
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Adrian Herber9 years ago
@Paul Johnson: Windows 8 and its App Store may pan out well for developers and consumers, but I can't see a good ending for Steam. On x86 platforms, Steam will be to the Windows App Store what Netscape/Firefox/Chrome are to Internet Explorer: the superior option that a lot of people can't be bothered installing becuase the built-in option works. And then there are the ARM-based Windows 8 devices that MS are quite keen on, which Steam can't be installed on at all. I think it's safe to say there is more to this than license fees.
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Dave Wolfe Game Developer, Cosmic Games9 years ago
To add to Adrian's comment, I think another reason for going with Linux is that Valve can have more control over the OS. They could even make their own distro focused on gaming and compatibility with their hardware, and even build Steam into the OS, or at least add tighter integration. Developing for a specific distro is also easier than trying to make your game work on all of the hundreds of different variations of Linux. There are many advantages to going with Linux other than just licensing fees.
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