Spec Analysis: Nvidia Project Shield
Digital Foundry's take on the GPU maker's surprise handheld announcement.
An Android gaming handheld with physical controls that can also wirelessly stream PC gameplay, NVIDIA's Project Shield is the surprise package of this year's CES show - a portable games machine that supports a massive range of games, from the most basic 2D Android titles through to the power and majesty of top-end AAA epics like Battlefield 3 and Crysis 2 via its innovative in-built local cloud gaming technology.
NVIDIA's Project Shield reveal was important for a number of reasons - not only did we see the company's first foray into handheld gaming territory, but we also witnessed the capabilities of its latest mobile hardware. NVIDIA reckons that its new Tegra 4 chip is the most powerful mobile processor in the world, and one more step towards closing the gap with the current-gen console standard set by the Xbox 360's Xenos graphics core.
Demos showing Dead Trigger 2 and eagerly anticipated free-to-play title Hawken looked a cut above most of the mobile titles we've seen, although they still fall short of the current-gen standard. Performance looked a bit wobbly, with Dead Trigger regularly dipping under 30 frames per second, but as we've discovered from iOS devices and indeed Tegra 3 hardware, HDMI mirroring appears to incur something of a performance hit, presumably owing to bandwidth limitations on mobile hardware. Until we get the device in our hands, we're not going to be able to ascertain exactly what this new hardware is capable of. NVIDIA's claims of 6x performance in relation to Tegra 3 will be quite some achievement though.
CPU-side, the Tegra 4 boasts a quad-core implementation of ARM's next-gen A15 CPU architecture, which it claims is a first. To illustrate the computational power, it compared a series of web pages being loaded on a Google Nexus 10 next to a prototype Tegra 4 tablet. The result was remarkable - Tegra 4 completing the tasks in 27 seconds while the Nexus 10 lagged home in a somewhat less impressive 50 seconds. While we have no doubt that the quad-core A15 configuration packs some serious power, we were a little disappointed that NVIDIA chose to compare the Nexus running Chrome while its own tablet appeared to be running the standard Android browser - this was not an "apples to apples" comparison with many believing that Chrome runs more slowly than the older browser [Update: error corrected].
Other elements of the Tegra 4 chipset also impressed (though we don't know if we'll find them in Shield) - particularly the CPU/GPU-assisted HDR photography mode, which includes panorama support. Definitely in is the ability to play back 4K video via HDMI, and you should expect to hear a lot more about this extreme 3840x2160 resolution specification. There have already been rumors that Sony's next-gen console may support it, and 4K gaming is something we'll be looking into in due course.
In terms of the Shield itself, the physical controls aspect warrants some discussion. NVIDIA's contention is that gamers are lugging wireless pads along with them so that they can enjoy the benefits of physical controls on their smartphone and tablet games. Its solution is to build a controller with a flip-top 5-inch LCD panel. The controller itself is clearly shaped with the Xbox 360 pad in mind and replicates all of its primary functions, adding Android buttons to the center cluster in addition to the start, select and shield buttons (the shield replicating the function of the Xbox 360's 'Guide' button). Speakers are integrated, which NVIDIA says possess excellent sound quality particularly in terms of bass reproduction.
All of the controls are recessed in order to allow the screen to sit flush with the rest of the casing once the unit is closed, with the lid allowing for the addition of custom decals. In terms of bulk, NVIDIA aimed to design a unit that isn't much larger than the standard Xbox 360 pad, and while it obviously looks a little larger owing to the integrated touch-screen, the firm's size comparisons to the 360 and Wii U GamePads looks fairly favorable. Also of interest is the teardown video (rendered in real-time on PC using Unreal Engine 4) giving us some hint of the innards. What stands out is the meaty heatsink attached to the Tegra 4 processor. Our analysis of Tegra 3 proved inconclusive, and according to hackers who contacted us, the full power of the hardware is held back by extreme power management - battery life being more important than games performance. The inclusion of the heatsink, plus the fact that this is games hardware from NVIDIA, makes us hope that this isn't so much of an issue. It's also worth pointing out that the Ouya Tegra 3 devkits feature an active cooling element, so the firm's claims of improved performance may well hold water.
In terms of design, console controllers have typically been dominated by a Japanese-style approach, whereas Project Shield owes more to the bright 'n' brash Alienware aesthetic. It's not the most compelling element of the hardware from what we've seen so far, but we'll reserve judgment until we've been hands-on.
Localized cloud gameplay
A genuinely exciting element of Project Shield is the ability to utilize its onboard video decoder for streaming gameplay from PC systems equipped with Kepler GTX graphics cards - the entry-level offering being the surprisingly capable GeForce GTX 650. This feature is Kepler-only, owing to the onboard h.264 video encoder incorporated into the silicon. Instead of rendering out completed frames to the display, Kepler encodes them at the driver level with no hit to CPU performance and the PC beams out the video feed to Shield. The new handheld decodes the stream and transmits control inputs back to the PC, the whole process taking place over Wi-Fi.
The result is a gameplay experience similar to what we find with the Nintendo Wii U, and in theory every game available on your PC should be able to be streamed over to the Shield (NVIDIA taking time to point out that the Steam library in particular is compatible). In essence, what we are seeing here is a localized rendition of cloud gaming, with NVIDIA utilizing the higher bandwidths and lower latencies inherent in a home network to overcome the genuine quality issues we witnessed with OnLive in terms of dodgy picture quality and muggy controls.
We have high hopes for Shield's streaming performance considering the overall hardware and software set-up. First up, there's the fact that the device has a 1280x720 screen. PC-side, there's no apparent on-screen rendering, meaning that the software can pour all of its resources into a native 720p framebuffer, so even the entry-level GTX 650 should be able to produce decent visuals and frame-rate on virtually every game. Secondly, the resolution limit means that vast amounts of bandwidth won't be required to maintain excellent image quality - 15-20mbps would be lavish by OnLive standards and unattainable on the majority of broadband internet connections, but should be easy to work with on any modern router.
In the home, we should see massive improvements to latency over the OnLive experience too, not just because of the more localized environment, but also owing to the way that the h.264 encoder will have access to the completed framebuffer without having to scan-out from the video output. Provided the panel chosen by NVIDIA for the Shield is fast enough, there's every reason to believe that the whole process could be completed with latencies close to that of the average HDTV.
NVIDIA also hinted heavily that in the future we should expect to see the streaming experience strike out from the home, presumably owing to the LTE modem contained in the new Tegra 4 processor (though previously we'd been led to believe that LTE would end up in a separate Tegra 4 revision). Previously, Gaikai's David Perry had ruled out streaming gameplay over existing 3G networks, suggesting that the latencies were just not good enough for decent response, citing the new 4G standard as the best platform for mobile cloud gaming. Obviously performance here in terms of NVIDIA's set-up is going to be dictated not just by the network, but also by the upstream connection at the user's home where the GTX PC is situated. UK fiber upload speeds are around the 8mbs level - serviceable enough but not completely ideal. Clearly though, sub-1mbps ADSL would be a complete write-off.
Project Shield: The Challenges Ahead
Overall, Project Shield looks like an intriguing convergence of cutting-edge mobile technology along with a gateway to high-end PC gaming in a more mobile form-factor, but there are clearly some concerns - the first of which can be summed up quite nicely by utilizing one of NVIDIA's own roadmap slides. Here we see the evolution of the mobile Tegra line, based on their superhero-themed codenames. Kal-El is the existing Tegra 3 while Wayne is almost certainly the Tegra 4 chip found in Project Shield. As you can see, the rate of technological progression in the mobile space is simply phenomenal - there's always an enormous leap in performance just around the corner. We have to wonder if rapidly evolving tech with yearly updates is the best basis for what a form factor traditionally associated with a fixed platform.
This isn't quite so much of an issue with multi-purpose tablets. Taking the iPad as an example, resale values remain pretty high since gaming is just one part of the package - the product isn't defined by the 3D power of the titles on offer and upgrading every couple of years isn't especially painful once you're on the ladder. Our concern with Shield is that staying on the cutting edge of 3D performance could be a whole lot more expensive and Tegra 4 could date quite quickly. It's worth bearing in mind that NVIDIA is just the first vendor to break cover with its next-gen mobile GPU parts, and if even half of the rumors we've heard from well-placed sources about the PowerVR Rogue technology are true (Xbox 360 performance with DX11 GPU features, in a nutshell), we could find a situation where NVIDIA is swiftly outclassed technologically, as was the case with Tegra 2 and 3 before it.
That said, the counter-argument to that is that there's a strong reason why products like the iPad mini and the Google Nexus 7 are great little gaming machines despite utilizing now-outdated processing technology: mobile games need to run on a wide range of devices and developers tend to target the capabilities of the most popular hardware, which is rarely the latest and greatest. Dead Trigger 2 and Hawken look really good, but these are games presumably designed to scale across a range of devices and so perhaps not the best showcase for Tegra 4. Also consider that the leaps in mobile processing power are being used to address displays with increasingly gargantuan resolutions. This is something that Shield doesn't need to worry about as much with its native 720p display.
Obviously there are more practical concerns, brought into sharp focus by the deeply disappointing experience offered by the Archos GamePad - how well does the Android OS transition onto the system, how good are the physical controls, how does the device feel in the hand and do NVIDIA's battery usage claims correlate with real-life usage? And then there's the really big question mark here - just how much is this new handheld going to cost? With Project Shield due in Q2 this year, hopefully we'll be able to get some answers - and some hands-on time - soon.