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Project Café Analysis - The GPU

Project Cafe Analysis

Also, while the rumours say that the CPU isn't going to be based on Fusion, it could share some similarities with AMD's CPU and GPU in one design. After all, the Xbox 360's Xenon chip is currently fabricated at GlobalFoundries; AMD's former fabrication wing. Not only that, but the CPU and GPU in the Xbox 360 S are now combined into a single package (called an XCGPU), combining an AMD GPU and a triple-core IBM PowerPC chip in one unit.

If GlobalFoundries can do this for Microsoft, then we'd imagine it will be able to do it for Nintendo too. Combining the two into one package will not only help Nintendo to keep down costs, but will also enable it to cut down on PCB real estate – both areas that have been key for the company in recent years.

Nintendo Project Café Rumour Analysis Project Café Analysis - The GPUIf GlobalFoundries can put a Power PC CPU and ATI GPU into the same package for the Xbox 360-S, then there's no reason it can't do the same for Nintendo (photo courtesy of PC Perspective)

The Graphics Chip

The difference, of course, is that Project Café looks set to have a very different GPU design from the Xbox 360. Back in 2005, 48 unified stream processors (or ALU pipes, as Microsoft called them back then) was revolutionary, but it now looks pretty weedy compared with the 1,536 stream processors found in the Radeon HD 6970 2GB. Of course, the 48 scalar units found in the Xenos GPU are not directly comparable to the stream processors found in AMD's Radeon HD PC chips, but there's still a gulf between them in terms of graphics processing power.

According to IGN, Project Café's GPU will be based on a 'revamped' version of AMD's R700 GPU, which will out-perform the GeForce 7-series GPU in the PlayStation 3. This doesn't give us a lot of information, though, seeing as the R700-series spanned chips with everything from 80 to 800 stream processors.

Given that there seem to be some big claims being made about Project Café's technical superiority to the PS3, it seems a reasonable guess that its GPU isn't going to have 80 stream processors and a crippling 64-bit memory interface - particularly if it is indeed going to output at 1080p (1,920 x 1,080) resolutions. However, the amount of power and cooling needed for 800 stream processors in a cramped space isn't going to make the Radeon HD 4850, 4870 and 4890 GPUs look attractive for use in a console either.

We're not going to completely rule this out, seeing as we're now dealing with 40nm transistors, which are much smaller and power efficient than the 4800-series' original 55nm manufacturing process. The process shrink could - if it's used - also help lower the cost of each GPU. However, if we were to make an educated guess, we'd say that the GPU is likely to be based on something smaller and less complicated than the 800 stream processor GPU.

Nintendo Project Café Rumour Analysis Project Café Analysis - The GPUA 40nm chip based on the Radeon HD 4670 could provide a sensible balance between speed and thermal/power requirements in a cramped space

For example, the Radeon HD 4670 had 320 stream processors (the same as the top-end parts from the Radeon HD 2000 and 3000-series), but only required a small cooler, and didn't require additional power connectors either. Produce a chip such as this on a 40nm process, and you potentially end up with a small, low-power chip with adequate gaming horsepower.

We say 40nm, rather than 28nm, simply because historically Nintendo has usually chosen to use chips produced on a tried and tested manufacturing process, such as the 90nm CPU in the Wii, rather than taking a risk with new processes. Technical prowess and bragging rights have never been as important to Nintendo as reliability and keeping down support costs. The Wii might have been grossly underpowered, but it also never suffered from the Xbox 360's red ring of death, or the PlayStation 3's over-heating problems.

Despite the fact that Project Café looks set to be several times more powerful than the Wii, the rumoured specs have also resulted in a fair bit of mockery online. After all, even 800 stream processors would be pretty weedy compared with a gaming PC, and fewer than this would make it look comparatively anaemic...