Forza Motorsport PC modded: extra detail and improved ray tracing are there for the taking
Plus: a look at performance optimisation since launch.
There was some level of disappointment when the long-awaited Forza Motorsport finally arrived for review, as visual quality didn't quite meet expectations - especially as promised features like ray traced global illumination didn't arrive in the final game, while PC technical performance was troublesome. However, a short while ago, we learned from user LJT that the PC game can be modded to add extra detail, improved RT reflections and RTGI, while reports of improved performance since launch warranted some investigation. So, how does the mod improve visual fidelity and what are the performance implications? Have CPU and GPU optimisations delivered performance boosts over the launch game? We decided to find out.
Engaging the mod turns out to be stupendously easy. Simply turn everything to max settings on PC, then visit the c:\XboxGames\Forza Motorsport\Content\Media\PCFamily\RenderScenerios folder on the Xbox version or the c:\Program Files\Steam\SteamApps\Common\Forza Motorsport\Content\Media\PCFamily\RenderScenerios folder on Steam. Here, you'll discover folders for each visual preset… along with a curious 'Visual Target' folder. And it's there that you'll discover a big bunch of XML files to upgrade the visual quality of the game. Copy those XML files into the 'Ultra' folder, overwriting what's there and you're good to go.
Before we progress though, bear in mind that this is an unofficial mod and you are enabling features that may not be complete, may cause visual artefacts or may crash the game. Also, don't expect your mods to work everywhere in all areas of the game: replays, cinematics and car inspections seem to lack the upgrades to ray traced reflections, for instance, but the improvements are present in gameplay.
With the mod enabled, one of the first things I noticed was a general increase in level of detail, draw distance and even object density when the mod is enabled. Grass is mostly a flat texture, for example, but with the mod, thin planes of geometry are added, stretching out into the distance. Extra detail and further draw distance are present in many other aspects of the game: denser forests, more bushes, stands packed with onlookers. All things considered, the game looks more dense, holding up better at a distance with less pop-in. This alone could form the basis for an 'extreme' visual preset in the shipping game - but there is more.
Also included is ray traced global illumination. This feature was promised at some point pre-launch and Turn 10 has been quiet about it, even though the technology does seem to be enabled on at least some of the firm's more recent marketing screenshots. RTGI traces light from the sun and even emissive surfaces (like LED hoardings for example), with accurate colour bounce transforming scenes.
RTGI's superior ambient and bounce lighting applies to all trackside buildings and detail, no matter how mundane, elevating the game's presentation. It takes areas that usually are overly bright and uniformly lit, adding in new pockets of darkness that make physical sense, grounding them into their surroundings. It is not just added shadowing of course, but added bounce lighting is important too, which illuminates surfaces with the colour of the surface the light reflects from.
By and large, it's an outstanding improvement - but the current implementation is not without its issues. Denoising generally works but it seems unfinished, meaning there are some cases where firefly light sparkles and other noisy artefacts are obvious, so while RTGI greatly increases lighting quality on the track, there are scenarios where the image is less stable.
It's not just about RTGI though as RT reflection quality is also greatly improved as the roughness cut-off is pushed out significantly. Essentially, RT reflection performance can be increased by lowering this cut-off, ensuring the effect only applies to 'shinier' surfaces. By increasing the cut-off, the effect applies to duller, or rougher materials. A good example of this can be found inside the cockpits of the cars, where subtle reflections now apply to materials like leather, nicely enhancing the realism of the interior. RTGI and enhanced reflections can combine nicely in this scenario, turning a jet black cockpit surround into something a lot more revealing. However, it's here with noisy artefacts are highly noticeable.
In general, the RT upgrades look great - but they aren't quite ready for the shipping game. While raining, reflections on the road do not present correctly with the mod engageg. Meanwhile, in night-time racing, a lot of lights lose their shadows for reasons unknown, giving the game an overly diffuse look. So, if you are interested in checking out the mod, stick to day races with clear weather if you can.
As you might imagine, the performance hit of all of these improvements is considerable - but the extent of the drop to frame-rate depends on context. Using an RTX 3080, when looking outside of a car where the primary difference is RTGI and extended draw distance, there is a significant 27 percent performance decrease. When tested in a replay (where the extended RT reflections are not present), that reduction in performance in the chase cam view was roughly 16 percent on average. We'd recommend having the camera this distance, generally, as cockpit frame-rate hits are high: in one shot, we saw a drop of 40 percent - do keep in mind that full reflection coverage and RTGI together can be rather expensive.
Beyond the mod, we had some issues with the PC version of Forza Motorsport at launch - primarily down to CPU performance, which seemed overly heavy and 'spiky'. On a mainstream Ryzen 3600 we would expect similar performance to the Xbox console, but frame-times were a little too high to achieve a locked 60fps, while jumps to around 33ms could cause stutter. Re-testing this week, there is clear and welcome improvement: on average there is a 15 percent improvement in frame-rates when CPU-limited. However, the boost will 'feel' better as the frame-time spikes are greatly reduced. On the GPU side, there are also improvements, but testing on an RTX 2070 Super, there improvement is just four percent - but nice to see nonetheless. It was also nice to see that the game now gives you clear and visible warnings if your settings selections take you beyond the limits of your graphics card's VRAM.
Overall, I'd say that Forza Motorsport on PC has reached a good point in terms of performance. Regarding the 'visual target' mode, it is obviously demanding on your GPU and has some visual issues, but I do think it's worth checking out - but more to the point, there's plenty of evidence here that Turn 10 could introduce a new 'extreme' graphics preset: enhanced detail and draw distance, improved RT reflections and RTGI would be great additions - assuming the bugs and denoising issues can be improved - if not for the mainstream hardware of today, then for the PC technology of tomorrow.