There’ll be all the specs you’ll need in this piece, but the reason Microsoft flew us out to talk to those involved was straightforward: the numbers, as impressive as they are, don’t fully represent what the final product aims to deliver. Nor can the number of compute units and teraflops represent the passion the Xbox team has injected into this project. Microsoft has a point to prove. It’s not just about performance, it’s about pushing the quality of console design to a new level – in all areas.
The headlines? Combining smart design with sheer horsepower, Project Scorpio hits the six-teraflop target set for it as E3 last year, thanks to a custom GPU that has been designed from the ground up for optimal performance on today’s game engines – and that runs at an unprecedentedly high clock speed for a console. The GPU is paired with 12GB of fast GDDR5 memory and a custom eight-core CPU, and the whole thing is housed in a compact body with integrated power supply and, for a console, state-of-the-art cooling.
Performance is remarkable. We saw a Forza Motorsport demo running on the machine at native 4K and Xbox One equivalent settings, and it hit 60 frames per second with a substantial performance overhead – suggesting Scorpio will hit its native 4K target across a range of content, with power to spare to spend on other visual improvements. And while 4K is the target, Microsoft is paying attention to 1080p users, promising that all modes will be available to them.
The push for 4K and the Scorpio Engine
In Redmond, the pitch comes thick and fast before the tech deep dive kicks off. The overall outline of Project Scorpio has evolved since Phil Spencer presented it at last year’s E3, and in some key respects it sounds familiar to the PlayStation 4 Pro’s proposition – a point not lost on Microsoft. 4K ultra HD visuals to suit the new generation of televisions are clearly the target, but Microsoft’s solution means substantial spec upgrades over the Pro design in virtually all areas. That said, Sony’s philosophy of ‘smart’ GPU design is also in effect here, executed in a very different manner, and backed up with a lot more horsepower.
Core to the new console is the Scorpio Engine, the new SoC (system on chip) developed once again in conjunction with AMD. In common with many aspects of the box, engineering the new processor was based on a revolutionary workflow – one that could only really be achieved on a mid-generation refresh design.
|Project Scorpio||Xbox One||PS4 Pro|
|CPU||Eight custom x86 cores clocked at 2.3GHz||Eight custom Jaguar cores clocked at 1.75GHz||Eight Jaguar cores clocked at 2.1GHz|
|GPU||40 customised compute units at 1172MHz||12 GCN compute units at 853MHz (Xbox One S: 914MHz)||36 improved GCN compute units at 911MHz|
|Memory||12GB GDDR5||8GB DDR3/32MB ESRAM||8GB GDDR5|
|Memory Bandwidth||326GB/s||DDR3: 68GB/s, ESRAM at max 204GB/s (Xbox One S: 219GB/s)||218GB/s|
|Hard Drive||1TB 2.5-inch||500GB/1TB/2TB 2.5-inch||1TB 2.5-inch|
|Optical Drive||4K UHD Blu-ray||Blu-ray (Xbox One S: 4K UHD)||Blu-ray|
“As we landed on 4K, Andrew [Goossen] and team did a pretty deep analysis,” Gammill continues. “We have this developer tool called PIX [Performance Investigator for Xbox]. It lets us do some GPU trace capture. He and his team did a really deep analysis across a breadth of titles with the goal that any 900p or better title would be able to easily run at frame-rate at 4K on Scorpio. That was our big stake in the ground, and so with that we began our work speccing out what the Scorpio Engine is. It’s not a process of calling up AMD and saying I’ll take this part, this part and this part. A lot of really specific custom work went into this.”
“What we did was to take PIX captures from all of our top developers… By hand we went through them and then extrapolated what the work involved would be for that game to support a 4K render resolution,” says Andrew Goossen, Technical Fellow, Graphics. “Now we had a model for all of our top-selling Xbox One games where we could tweak the configuration for the number of CUs, the clock, the memory bandwidth, the number of render back-ends, the number of shader engines, the cache size. We could tweak our design and figure out what was the most optimal configuration. It was incredibly valuable for us to be able to make those trade-offs, because ultimately these Xbox One titles are the ones that we… wanted to get up to 4K.”