Earlier this month, Eurogamer’s Digital Foundry was given an exclusive look at Microsoft’s Project Scorpio. The specs sure sound promising which include an eight-core custom Jaguar x86 (evolved) CPU, GPU having 2560 cores, 6 teraflops compute performance, and 12GB GDDR5 RAM.
Recently, more details regarding the Scorpio Engine SoC have surfaced via Digital Foundry, revealing technical aspects of the chip that powers the new Xbox. The article discusses the processor architecture in great depth, however, we’ll only focus on the GPU part of the SoC.
Project Scorpio’s GPU: Vega in design, Doesn’t Support Double FP16
We know that the Project Scorpio is based on AMD’s latest Polaris architecture. According to details, the GPU heavily modified and there is no equivalent part to it in the PC space. While the graphics chip is mostly Polaris-based, there are some performance optimizations from the next-gen Vega GPU architecture as well, that have made it into the console’s design.
But when compared with the PlayStation 4 Pro, you may find that some features of the Pro’s GPU has made it to the Scorpio. One of those most talked-about features is the double-rate FP16 processing. That won’t degrade the performance though; in fact, Project Scorpio is faster on the GPU, claims Andrew Goossen, Technical Fellow at Microsoft.
You might think, oh you’re sending more commands to the GPU now, maybe you’re slowing down the GPU. Well, very rarely are we draw-bound on the command processor. And the nice thing is that even when we are draw-bound now in D3D12, again we are more efficient even from the GPU perspective, because we’re built-in.
We don’t have a very big and noisy and abstract interface we have to deal with. We just have the logic built right into the command processor, and in the command processor we can do more optimisations than we can in the driver.
With Scorpio, what Microsoft actually did is that they created a silicon around the software. They analyzed how the Xbox One runs the software, where the bottlenecks are, and then they asked AMD to get rid of those in the new piece of silicon being created for the Scorpio.
That is how the Project Scorpio Engine was designed around the software – and not the other way around. Which may be actually a big win for Microsoft.
Scorpio to have performance benefits over PC
Since its announcement at last year’s E3 event, Microsoft has touted Project Scorpio at every turn, calling it be the most powerful console ever made. Xbox boss Phil Spencer recently said in a Q&A session that the new console actually surpassed their expectations so far when it comes to performance gains.
They are not even afraid to compare it to a PC. When asked to compare Scorpio with a PC equipped with an equivalent GPU with the same number of TFLOPS, Goosen replied:
We put every change we considered through the model. But in terms of ‘more from your teraflops’, I will point out that Scorpio has significant performance benefits relative to PC.
There are several adjustments made to the Scorpio to achieve this level of performance, suggests Goosen. First, Microsoft has made continual improvements to the shader compiler, which now works more effectively than the same shaders on a PC.
In addition to this, the API has been developed from the ground-up for the specific hardware. This, together with the shader extension support, would result in an optimisation potential which practically isn’t possible with PC cards.
Last but not least, the Performance Investigator for Xbox (PIX) provides a deep insight which helps developers better optimize their games.
Whether Microsoft will be able to deliver on its promises, is hard to ascertain at the moment. Project Scorpio is planned for a Holiday 2017 release, but you can expect more details such as price and games for the console, to be revealed at this year’s E3 in June.