Metro Exodus Enhanced Edition - the ray tracing showcase tested on Xbox Series X/S
Built from the ground up for RT, but can consoles really deliver 60fps?
We've already taken a deep look at Metro Exodus Enhanced Edition on PC and were genuinely impressed with its phenomenal ray tracing - perhaps not surprising when the new 4A Engine is built from the ground up with hardware-accelerated RT hardware in mind. However, the question we could not answer at the time was simple enough: how does that experience translate to the new wave of consoles? Is there enough horsepower on tap to deliver a state-of-the-art 60fps ray tracing showcase? We've now had the chance to test the game on both Xbox Series X and Series S hardware - and the results are excellent.
Comparisons up against the last-gen versions are entirely valid and looking at Xbox One X as the best of the lot, the new game is transformed. Yes, you're getting twice the frame-rate (last-gen topped out at 30fps) but it's the transition to an RT-based aesthetic that makes all of the difference. The rasterised real-time global illumination system of the old version looked fine, but ray tracing takes fidelity to the next level. All of the old artist-placed lights are gone, replaced with a fully ray traced alternative that 'just works'.
Light from the sun, the moon - or objects that emit light - taps into RT, illuminating any given scene with accurately calculated light bounce. The original Metro Exodus's PC RT solution shipped with just one light bounce, while the Enhanced Edition - even on consoles - works with infinite bounces, calculated over time. As a consequence of this, usual screen-space ambient occlusion (SSAO) isn't required. It's all part of the global GI solution delivered by ray tracing. It's also far easier to show rather than tell, so please check out the video embedded below to appreciate how this technology works.
Ray tracing also plays a part in how reflections work in Metro Exodus, though it shouldn't be confused with the mirror-like RT effect seen in, say, Ratchet and Clank on PS5 - or even the PC version of the Enhanced Edition when fully enabled. The standard technique is screen-space reflections, which takes the rendered scene and maps that data onto reflective surfaces. The problem with this is that it cannot show things that reflect which are not on-screen, or are occluded by, say, the view weapon. Cubemap approximations - static 'samples' of the scene - are mapped into these areas without screen-space data to help preserve the effect, with varying levels of success. The Enhanced Edition on PC keeps SSR, but uses ray tracing to fill in those gaps - an accurate but expensive implementation. The console rendition, meanwhile, sticks with SSR but uses global illumination data to fill in the missing image data. PC ups the ante, but the console version still delivers a more natural look than the last-gen version.
All told, when viewed side-by-side with the old game, the visual improvement is profound. The realism is on another level, to the point where the lighting elevates the look of the game in a genuinely 'next-gen' way. It's incredible stuff. However, necessarily, there are further differences between the PC version and the new consoles - whether it's RDNA2 AMD hardware or GeForce RTX, there's more power and performance available to RT features, while Nvidia's DLSS provides a huge accelerant. The most basic optimisation is the use of PC's 'normal' RT setting, which essentially calculates the ray traced effects at quarter resolution.
In terms of overall settings comparisons up against the PC version beyond that, there's no tessellation in play, the tier one VRS solution is ramped up to the maximum 4x, while RT reflections look the same as PC's 'off' setting. Elsewhere, 4A chooses from a grab bag of medium, high and ultra settings for other elements in the game. Dynamic resolution scaling is firmly in play, with native resolution operating at anything between 1080p and a theoretical 2160p, though 1728p was the highest I saw on Series X. Resolution is a constantly moving target, it's fair to say. We've not seen how PS5 stacks up against Xbox Series X just yet (more on that soon) but we'd imagine the two consoles to be broadly equivalent - but Xbox Series S is an altogether different proposition. Many developers, including heavyweights like id Software, are shying away from RT on Microsoft's junior console, but this is not an option for 4A, who've built their entire technology around a ray tracing-based workflow.
It's still targeting 60fps, but resolution drops dramatically, which shows up more artefacting and grain on the RT-based global illumination solution. 1080p is the target resolution but in common with all versions of the game, dynamic resolution and temporal reconstruction are deployed, accumulating data from prior frames to increase quality of the current one. While 1080p is the target, I feel that the console rarely attains it, with 864p the more usual pixel count - maybe lower, depending on the content. Where the game is at its heaviest in the Taiga level, the game attempts to reconstruct up from 512p - and even in stills, the image quality suffers significantly. Where VRS is employed, the blockiness at low resolutions is clearly visible, partly down to the fairly limited nature of the tier one implementation.
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The most visible deviation in settings from the Series X is that the distance for scattered objects like grass and rocks is much lower, resulting in more obvious object pop-in. So, the Series S definitely has compromises that are visible but given the GPU power available, they make a lot of sense if the goal is to hit 60fps with ray traced global illumination - and really, at its best I still found the Series S version attractive in its own right, just not exactly sharp. That said, a 30fps quality mode may have been useful, though reduced refresh rates may have implications for the way that the RT global illumination system accumulates data over time.
The question is whether 4A's ambitious 60fps gambit pays off? The answer is by and large 'yes', albeit with a caveat: as the game relies so heavily on dynamic resolution scaling, and because the content is so variable, there can be times where the 1080p and 512p minimums for Series X and Series S are not enough, resulting in performance drops. Thankfully, the frequency of this issue is limited - occurring just a handful of times in my playthroughs. Most of the time we are at a flat 60fps, though there can be some stutter during traversal, or when multiple enemies are on the move. I'm not sure what's causing these issues, but this is more noticeable than the drops seemingly caused by hitting the lower bounds of the dynamic resolution range.
Ultimately though, Metro Exodus Enhanced Edition is a success on consoles - and an important one, being the first major triple-A quality game engine to transition entirely to an RT-based foundation. The new game looks a lot better than the last-gen version, frame-rate is doubled, and even with some visible optimisations and cutbacks compared the PC version, the game still shines brightly thanks to the stunning global illumination technology. If you'd asked me two years ago if we would be seeing a console game running at 60fps and built on an ambitious real-time RT GI solution, I would have scarcely believed it possible - and yet here it is. 4A has delivered amazing work and I highly recommend checking it out, and we'll return as soon as we can with a look at the PlayStation 5 rendition of the game.