Digital Foundry has uncovered a whitepaper from Microsoft aimed at developers. In this white paper, Microsoft explains what the Xbox Scorpio can mean for developers and how they can make use of the improved specs. If we can trust Digital Foundry (and it seems, but they are not official specs yet) then the Scorpio looks like a fine 4K gaming machine.
Digital Foundry has a whitepaper in its hands that was distributed to developers shortly after the unveiling of the Scorpio at E3 last year. The whitepaper gives an interesting look at the possible specs of the Scorpio and what developers can do with the extra horsepower. Keep in mind that Microsoft has not yet confirmed these specs, so keep the salt shaker handy for now.
The biggest change that the white paper describes is the removal of ESRAM from the processor die. The Xbox One and Xbox One S had a small amount of embedded SRAM (static internal memory that is much faster than normal internal memory). Microsoft hoped to compensate for the relatively slow DDR3 memory of both models. With the arrival of the Scorpio, Xbox says goodbye to the 32MB on-die ESRAM, so they can use the space on the die to get the target six teraflops on the GPU.
The Xbox Scorpio must become a dedicated 4K HDR device, freeing up space on the die for more computing power is therefore not a crazy move. That GPU is in any case built on the Polaris microarchitecture, but if Microsoft has started working with AMD early enough, we may see the newer Vega architecture appear in the Scorpio. Developers must still take into account the ESRAM on the older models, because no games (or versions) that are exclusive to the Scorpio are allowed.
In the whitepaper, Microsoft recommends a few tricks to achieve the target 4K HDR: do not render everything at 4K, but keep unimportant things such as filters and lighting effects at 1080p, or even 900p. By selectively rendering things at 4K, there is little loss in graphic quality, but games can run at a higher frame rate, or use the released GPU power elsewhere, according to Microsoft. In addition, developers can use checkerboard rendering and dynamic resolution scaling to achieve the maximum number of fps.
Then the CPU in short: eight cores, more similar L2 cache (four times as much to be precise) and probably no Zen architecture. According to Digital Foundry, given the timeframe, it is possible that we will see Zen CPUs in the Scorpio, but a passing note in the white paper suggests that it is not the case after all. In the quote, Microsoft advises not to go overboard with the extra CPU power, but to use it sparingly:
We acknowledge that developers may not wish to spend all of the additional GPU resource of Project Scorpio on resolution, and this is not mandated. To make the best games possible, developers will inevitably spend GPU resource on other quality improvements such as higher fidelity shadows, reflections, texture filtering and lower draw distances. Another option developers might consider is frame-rate upscaling – running graphics at 60Hz but the CPU at 30Hz and interpolating animation.
In that last sentence, Microsoft is actually saying that you shouldn’t use the Scorpio’s extra CPU power and instead upscale the animations running on the CPU. If the Scorpio does indeed use the Zen architecture, the comment is pointless, the extra power of the new architecture would be more than enough to accommodate the extra work of real-time animations.
All in all, it looks like the Scorpio is a step towards multi-platform development, where DirectX 12 allows developers to develop both for Xbox One, Xbox One S, Xbox Scorpio and PC at the same time without extra effort or code. In addition – provided these specs are correct – we can say that the Xbox Scorpio is a reasonable candidate for gaming at 4K.