The idTech 7 engine has evolved with the arrival of a new patch for Doom Eternal, adding ray tracing support for well-equipped PCs – and of course PlayStation 5 and Xbox Series X, which also receive 120Hz resolution and refreshes. But the RT implementation is the big star of the show, adding beautiful reflections on surfaces like water, glass, metal, plastic and even polished wood. The computer also benefits from Nvidia DLSS support, which means that even entry-level RT graphics cards like the RTX 2060 can deliver a great experience with next-generation features turned on.
So what’s the real motivation for incorporating RT reflections into a game like Doom Eternal? In preset settings, they combine with standard screen space reflections to form a “complete package” for a result that can have a transformative effect in a game with the kind of materials Doom Eternal uses – metals and shiny plastics – although coarse materials can benefit from the effect. Reflections accurately reflect types of surfaces and are more dynamic, to the point that surrounding and moving environments are drawn seamlessly onto appropriate surfaces – something standard cube maps can’t do.
I was also interested to see if particles were also present in the reflections – so shooting an explosion with a BFG in the distance, then rotating 180 degrees to look into a glass window, would see the effect repeat itself in the reflection, along with other elements of scene dynamics. Of course, the Doom Slayer itself is also in the reflections – even if they are rough. Doom Eternal uses the “floating hands” style of the real first person model, but the point is that with virtual reactions, the player isn’t there at all. Based on RT, based on the translation of light rays, all distortions in the material are precisely mapped – perfect mirror reflections occur only if the material itself is perfectly flat. Ray tracing also applies to every pixel, so even small glass objects like health flasks will show full RT reflections with original detail, if we look at them closely.
Here’s Alex Battaglia with Digital Foundry’s video analysis of the Doom Eternal RT update.
While we’ve talked about how Doom Eternal uses pure ray tracing, it’s important to mention that screen space reflections have been added “on top of” the ray tracing variant. This can have upsides like adding fog to reflections, but it can also lead to some inaccuracies around the pure RT approach (which is also available through options), but it increases performance. By the way, on the RTX 3080 at ultra-nightmarish settings, RT reflections reduce performance by 38 percent. This seems like a huge shortfall but the point is that Doom Eternal actually runs really fast – the worst case RT I could find is a 3.5ms render time, which is actually pretty fast. Not only that, quality can be reduced and performance improved – before we even think about a DLSS accelerator.
Looking at the reflection quality setting, I didn’t see any difference between Nightmare Ultra, Nightmare and Ultra – all three of these settings have the same cut-off in thickness and half-res reflections. Decreasing the thickness reduces the quality of the reflection, which means that fewer surfaces have RT reflections – and the resolution of these reflections decreases as you lower the settings. As you’d expect with its power, the PC is capable of producing much better RT quality than consoles running at 1800p resolution with the equivalent average PC reflection quality. This means less roughness cut and RT reflections with one-third accuracy. Beyond that, however, consoles go to Ultra PC quality settings in terms of visual quality, although the anisotropic filtering is pretty low by PC standards, while shadows of screen space seem to be absent.
All of this leads us to the inclusion of Nvidia’s DLSS, which again has the ability to match and even exceed the native resolution display in many respects – especially if the .dll file included in the game has been swapped out for the version shipped with Rainbow Six Siege (checks). Our content is here To see how much better this variant of DLSS 2.2 is over the already great 2.1). In fact, the RTX 2060 that uses DLSS benchmark for performance quality up to 1800p by 900p internally looks much better than either console version and does not degrade image with dynamic resolution scaling the way the PS5 and Series X do when overloaded (although Make sure this game supports DRS with DLSS if you like). The performance improvements are impressive – but keep in mind that the quality of RT’s reflection depends on the internal resolution of DLSS, so it can be degraded. Increase the setting there, or go to the command line and increase it further if you can – I’ll discuss how to do that later.
So we’ve proven that RT’s implementation in Doom Eternal is excellent and works very well on the GPU – but it’s also worth remembering that RT’s installation costs also have an impact on the CPU. The good news here is that idTech 7 is already very CPU efficient, to the point that a cheap Core i5 11400F can routinely run the game without RT at 300fps. Even the least capable (but most popular) Ryzen 5 3600 with RT enabled can deliver an experience in a 140-160 fps window.
Regarding the GPU, the performance will depend on your hardware – obviously. But my configuration recommendations here are simple. Nightmare and Nightmare Ultra settings provide additional fidelity, but greatly overload the GPU and CPU. These settings are so extreme that Nightmare Ultra turns off the level of detail, which means everything – Even sub-pixel details – will be rendered in full resolution. Instead, aim for ultra settings that are more balanced and look a lot alike. VRAM is also an issue in this game and anything less than 10 GB should lower the texture cache setting – as in practice this will have no real effect on the visual quality. It only increases the frequency with which textures enter and exit the GPU, with the highest possible chance that a quick camera shake or camera teleport will show a texture at a lower resolution for some frames. If you’re getting poor performance in Doom Eternal, it’s probably because of that. Long, medium and even short have a look.
In short, my recommendations are simple. Stay ultra connected for a truly high-end experience, but the lower the native resolution, the higher the RT reflection setting should be – especially with active DLSS on RTX GPUs. The higher setting uses half precision reflections, but entering the game console with the key and typing, r_raytracedReflectionsTemporalUpscaleQuality gives you 0 full quality reflections. Another modification is to increase the amount of surfaces that can contain ray tracing reflections. This is done by using r_SSRMinSmoothness and changing it to a value closer to 0. The closer we are, the more surfaces receive reflections. If you are having difficulty accessing these features or other command line functions, CheatEngine can help activate it.
We’ll still have to take a closer look at the console versions with different Windows resolutions and 120Hz updates, but in the end I’m very happy with the PC version of Doom Eternal as it stands right now. The performance with ray tracing is excellent, the DLSS implementation works beautifully to allow great results on low-end RTX GPUs (and gets even better with quick dll swapping) and I like the way the command line is for enthusiasts who really push the technology in whatever direction they want. Doom Eternal has always been an exceptional game – and the “Next Generation” update makes it even better.
