Tech Analysis: Nintendo Wii U

Six weeks before E3, Nintendo confirmed the existence of its next-gen console, Project Cafe, and the rumour-mill engaged at full pelt in leaking out an almost complete technical specification of the new console. A few red herrings aside, the information turned out to be eerily accurate in most key respects: the machine would have an IBM CPU, a graphics core from AMD and the centrepiece of the experience would be a brand new joypad controller, integrating a 6.2" touchscreen.

What was missing from the rumours and speculation was the key ingredient: the core concept behind the design - the special x-factor that would elevate this from a collection of familiar-sounding tech into a distinctive, must-have, next-generation Nintendo console.

The message from the platform holder at E3 was all about the controller. The introduction video kicked off by showing gameplay on an HDTV being transferred onto the tablet/joypad hybrid, then showed various other interesting concepts - touchscreen sketching using the stylus, remote play of simple games, the use of the controller as a pointing device with the player "throwing" stars at the screen and even showed the use of the tablet's camera with a videochat concept that looked very similar indeed to Apple's Facetime.

The machine gained a name: Wii U, and we learned that it could run all original Wii titles and is compatible with all existing peripherals. Existing Wii Remote Plus controllers were even shown used in split-screen multiplayer concept demos, in concert with the tablet pad.

The Wii U's controller is both technologically innovative and at the same time rather unsophisticated. On the one hand, the notion of a zero latency link between the controller and the screen is a hugely compelling proposition that has only just begun to be explored on PC, but on the other hand, the screen is bigger than PlayStation Vita's but seemingly runs with a lower native resolution. The touchscreen itself lacks multi-touch functionality; it's also resistive in nature compared to the capacitive spec of the iPad and most modern smartphones, requiring the use of a stylus for precision interaction.

In common with many of the more controversial elements of the Wii U spec, even the screen resolution has not been officially confirmed. However, a resistive 6.2-inch widescreen display sounds very much like the kinds of LCD screen utilised on satnav systems, so an 800x480 resolution with slightly rectangular pixels giving a 16:9 aspect ratio seems plausible and would tie-in with Nintendo's known modus operandi in sourcing off-the-shelf components and repurposing them in innovative ways.

Bearing in mind that the controller is the centrepiece of the Wii U offering, the overall spec of the screen does seem a little underwhelming, particularly when the demonstration video shown to E3 delegates even included a spot of web-browsing - a job ideally suited to a capacitive screen. A touchscreen-based keyboard is also going to be quite uncomfortable based on resistive technology - another factor counting against it as a browsing device.

There are other drawbacks too. If you look at the way the Windows 8 interface operates (or indeed a whole host of iOS games) with the emphasis on gestures and interaction with objects via multi-touch, it's clear that there are a great many gameplay opportunities here that Wii U will not be able to emulate. In this sense, Nintendo will be relying on the traditional joypad-style controls to make the difference.

The platform holder's focus has been on the potential of new gaming ideas based on the new controller, ranging from the obvious - RPG-style inventory screens on the touchscreen, gameplay on HDTV - to the rather more ingenious. Brand new multiplayer concepts such as "hide and seek" style gameplay were demonstrated where the one player has a private view using the touchscreen, while Wii Remote-toting players use the main display only.

The multiplayer aspects are certainly intriguing ideas, but we also see another limitation here - as of right now, only one of the touchscreen controllers is supported. Everyone else has to use a traditional Wii Remote Plus instead. This means that obvious applications for the technology (for example, privately choosing plays in Madden) won't work for two players gaming in the same room.

There are other challenges in pursuing a multi-screen approach to gameplay too. It's safe to say that the player's focus can only really be concentrated on a single-screen at a time, and switching focus in a fast-paced game is going to be something that could only be handled with very careful design. There's also the basic reality of RAM: even if we assume that the touchscreen will be handling very basic 3D rendering (or none at all), the Wii U is still going to require a set amount of memory put aside to deal with the multi-screen set-up.

A curious observation we made at E3 concerned the Wii U's use of video transmission technology to switch gameplay from the HDTV to the touchscreen. Nintendo's display featured both screen outputs running on external monitors. At several points we witnessed the transition of gameplay from the HD display to the secondary monitor, and noted that the images were being re-rendered at the lower native res as opposed to being downscaled. Interestingly, this could lead to higher frame-rates on certain games as the fill-rate requirement drops immensely moving from 720p down to 480p.

Looking at the positives, Nintendo has always made excellent game controllers with great ergonomics, and in terms of the size and shape of the Wii U tablet/pad, it's remarkably light and easy to use. Regardless of the provenance or resolution of the 6.2-inch display, picture quality looks good and while there is a clear resolution deficit up against the iOS Retina Display amongst others, the image is bright and sharp.

Whatever the reservations about the limits of the controller's technology, there's no doubt that in hand, the pad feels new and different, and while not quite as revolutionary as the Wii Remote was in its day, there's a feeling that the raw tools are there to create gameplay opportunities that are fresh and different, backed up by the same level of visuals we see on the current generation of HD consoles. And there's something extremely cool about the concept of disengaging from the lounge display and gaming remotely - let's just hope that there's a useful amount of range and decent battery life.

Another positive element is that while Nintendo has clearly concentrated on its tablet/pad concept, it recognises that it needs to be competitive with Microsoft and Sony in attracting third party developers to the platform. In partnering with AMD and IBM for the core components in the new machine, it has chosen the best possible collaborators, providing instant parallels to developers who are very familiar with the make-up of the Xbox 360. In going with this approach, game-makers should be able to hit the ground running and won't need extended periods of time to get to grips with a whole new architecture, as was the case with PlayStation 3.

Details are starting to emerge about the Wii U's hardware technology, limited as they are. IBM has confirmed a bespoke, energy efficient CPU design with a significant amount of embedded DRAM, operating on a 45nm process and based on the POWER architecture. The official IBM Watson Twitter account even goes so far as to confirm that the company's latest POWER7 tech forms the basis of the new CPU, but really it could be nothing else since IBM's prior CPU architectures don't actually have onboard DRAM.

Current POWER7 chips operate with anything between four to eight cores, each with eight threads and featuring access to 4MB of eDRAM. The more accurate end of the Project Cafe rumour mill suggested a tri-core IBM CPU, which would require a significant redesign of the existing architecture, but this doesn't seem too unlikely: POWER7 is a server-level CPU that's monstrously large compared to the typical console CPU, and with IBM confirming a 45nm fabrication process, a basic quad would simply be too large and too hot for the Wii U's diminutive form factor. Indeed, by our reckoning, it would be larger than the 90nm Xenon core in the launch version of the Xbox 360. We'd expect to see the CPU significantly cut-down from its server-targeted sibling, but even so, we'd still hope for a useful performance bump when compared directly against the 360's processor.

The Zelda HD Experience showed off PS3/360 levels of graphical power, but most of Nintendo's E3 offerings looked very much like Wii assets rendered at 720p.

Even less is known about the make-up of the AMD graphics core in the Wii U. The notion of it being sourced from the R700 line of AMD GPUs (a two-year-old design) seems likely, but very little evidence of the tech's capabilities could be discerned from the E3 demos.

The concept demos were effectively Wii-era visuals running at 720p with no anti-aliasing - not exactly a taxing graphical workout. The excellent Zelda HD Experience dazzled with a number of accomplished effects, lots of light sources and some phenomenal art, but was once again running at 720p with no AA. The most impressive tech demo, the Japanese garden, again seemed to be running at the same resolution and for all its grandeur, it suffered from frame-rate issues on some sections and appeared to have some notable texture filtering problems.

Few conclusions can be drawn from these demos of course, but it is notable that elements such as anisotropic filtering and multi-sampling anti-aliasing are hardware features that will have been built into the AMD core - quite why they were not being used is a bit of a mystery. Anti-aliasing in particular would have really made a difference to the clean aesthetic that was on display in the Wii-style demos.

There's been plenty of speculation of late about the raw processing capabilities of the Wii U, with the 50 per cent processing boost claim from the pre-E3 rumours once again getting an airing courtesy of Sterne Agee analyst Arvind Bhatia. Aside from the odd mention of 1080p (not reflected in the demos), Nintendo has made no effort to distance itself from the 3D capabilities of the current generation consoles to the point where it was happy to showcase PS3 and 360 footage of upcoming cross-platform titles to illustrate forthcoming Wii U releases.

Perhaps more telling are the recent comments from id software technical mastermind John Carmack. He pegs Wii U at the same level as the PS3 and 360, and believes there's plenty of mileage left in the current platforms.

"The technology level... brings it up to parity with the other consoles, which is nice for us," he told Gamespot.

"The current platforms are so powerful and so sophisticated. I don't think there's any person anywhere that can really honestly say they know everything about one of these platforms."

The only thing the press saw resembling an actual game at Nintendo's event was a five level co-op demo for New Super Mario Bros. Once again visuals were rendered at native 720p with no anti-aliasing.

Raw specifics on the Wii U GPU remain unclear, but even AMD's entry level enthusiast GPUs - the RV740-based Radeon HD 4750 and 4770 have an embarrassing amount of graphical power compared to the current Microsoft and Sony consoles. However, the cut-down HD 4650/4670 could be repurposed fairly easily into a tight, compact, efficient console GPU that would be a good match for the current generation consoles. By using modern GPU tech, Nintendo also gains other useful, non-rendering advantages. The Avivo video processing technology should give a significantly superior quality level compared to the first generation implementation seen in the 360's Xenos chip, resulting in superior upscaling and downscaling.

The compact form factor of the Wii U also suggests that Nintendo isn't pushing out the boat on an expensive, power hungry architecture. The machine itself isn't very large, and with a 45nm CPU and what we would expect to be a 40nm graphics chip, Nintendo could be in danger of precipitating another RROD disaster if it went for higher-end, performance-centric components. The pre-production unit at E3 looked to be smaller than the current Xbox 360 Slim - and it contained an internal power supply (something Microsoft continues to externalise), another source of additional heat.

Overall impressions of Wii U are positive if not spectacularly overwhelming once you've had the controller in your hands and you've got some idea of the approach Nintendo is going for with its new design. Rendering performance on a par with Xbox 360 and PlayStation 3 is absolutely fine so long as the concepts behind the games produce new and fresh experiences. That's the key challenge going forward, as John Carmack realises.

"I'm kind of excited about the touch-screen aspect on there," he says.

"I think that probably has broader general utility for games than most of the motion control stuff, where you really have to design a game around motion control and you can't just tack it onto a finely crafted FPS. But I think the DS has really shown what the extra little touchscreen can do - almost any game can do something useful with that."