Ever since Microsoft confirmed the rumors regarding the so-called Project Lockhart console, which turned out to be the Xbox Series S, the game development community has split on the implications of having a much weaker min-spec hardware to deal with compared to PlayStation 5 and Xbox Series X.
So far, the general consensus was that the main difference lied in the smaller and slower RAM. The Xbox Series X features 16 GB GDDR6 (320-bit bus), 10 GB of which run at 560 GB/s, while the remaining 6 GB run at 336 GB/s. The Xbox Series S hardware, by contrast, is limited to 10 GB GDDR6 (128-bit bus), 8 GB of which run at 224 GB/s, while the remaining 2 GB run at a mere 56 GB/s. The CPU is practically identical, with only a 0.2 GHz difference in favor of the Series X, while there are 32 more Compute Units in the Series X's GPU - but then again, the smaller sibling only targets 1080p resolution (or 1440p at best), while Series X is meant for the much more taxing 4K gaming experience. The resolution drop should be enough to equalize the GPU potential, or so it was believed.
In our exclusive interview published yesterday, though, 4A Games Chief Technical Officer Oleksandr Shyshkovtsov offered a different take. The Metro developers apparently found that the RAM was not an issue in their case, but the lower GPU performance of the Xbox Series S could prove to be a challenge in future titles due to the very nature of the 4A Engine renderer.
The RAM is not an issue for us (currently), but GPU performance presents challenges for future titles. Our current renderer is designed for high spatial and temporal resolution (read: 4K @ 60 fps). It is stochastic by nature. Dropping any of those would require us to do more expensive calculations dropping performance even further. We have a compromise solution right now, but I am not satisfied with it yet.
Going forward, 4A Games is working on a new Metro game, a Metro multiplayer spin-off, and a brand new IP. Metro Exodus will be updated later this year to run at 1080p@60 FPS on the Xbox Series S, featuring full ray-traced lighting, per-pixel ray traced GI, and ray traced emissive surfaces with area shadows.