There was some disappointment when the long-awaited Forza Motorsport finally arrived for review, as the visual quality didn’t quite live up to expectations – particularly as promised features such as ray traced global illumination didn’t make it into the final game, while the technical performance on PC was problematic. However, a while back we heard 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 the visual fidelity and what are the performance implications? Have CPU and GPU optimizations delivered any performance improvements over the launch game? We decided to find out.
It turns out that activating the mod is surprisingly easy. Just set everything to max settings on the PC and 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 will find folders for each visual preset… along with a curious “Visual Target” folder. And here you will find a large amount of XML files to improve the visual quality of the game. Copy those XML files into the “Ultra” folder, overwrite what’s there, and you’re good to go.
But before we go any further, keep in mind that this is an unofficial mod and you’ll be enabling features that may be incomplete, introduce visual artifacts, or crash the game. Also, don’t expect your mods to work everywhere in every part of the game: replays, cinematics, and auto-inspections, for example, seem to miss the upgrades to raytraced reflections, but the improvements Are present in the gameplay.
With the mod enabled, one of the first things I noticed was a general increase in detail, draw distance, and even object density when the mod is enabled. Grass, for example, is usually a flat texture, but the mod adds thin planes of geometry that stretch off into the distance. Additional detail and further draw distance are present in many other aspects of the game: denser forests, more bushes, stands full of spectators. All in all, the game looks denser, holds 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’s more.
Also included is ray traced global illumination. This feature was promised at some point before launch, and Turn 10 hasn’t said anything about it, though the tech does appear to be enabled in at least some of the company’s most recent marketing screenshots. RTGI tracks light from the sun and even emitting surfaces (like LED billboards, for example), accurately rendering scenes that transform color bounce.
RTGI’s superior ambient and bounce lighting applies to all the buildings and details along the track, no matter how mundane, and elevates the presentation of the game to a new level. It takes areas that are normally too bright and evenly lit, and adds new dark spots that make physical sense, grounding them in their surroundings. Of course, it’s not just added shadows, added bounce lighting is also important, illuminating surfaces with the color of the surface the light is bouncing off of.
Overall, it’s a great improvement, but the current implementation isn’t without its issues. Denoising generally works, but it seems unfinished, meaning there are cases where firefly light sparkles and other noisy artifacts are clearly visible, so while RTGI does significantly improve the quality of the light on the trail, there are scenarios where the image is less stable.
It’s not all about RTGI though, as RT reflection quality has also been greatly improved, thanks to the roughness threshold being significantly increased. Essentially, RT reflection performance can be increased by lowering this threshold, so that the effect only applies to ‘glossier’ surfaces. By raising the threshold, the effect applies to duller or rougher materials. A great example of this can be found in the cockpits of the cars, where subtle reflections now apply to materials such as leather, nicely enhancing the realism of the interior. RTGI and enhanced reflections can combine nicely in this scenario, transforming a jet black cockpit surround into something much more revealing. However, it is here with noisy artifacts that are very noticeable.
Overall, the RT upgrades look great, but they’re not quite ready for the shipping game yet. When it rains, reflections on the road don’t render properly with the mod engageg. Meanwhile, many lights in night races lose their shadows for unknown reasons, making the game look too diffuse. So if you’re interested in trying out the mod, stick to daytime races with clear weather if you can.
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As you can imagine, the performance hit from all of these improvements is significant – but the extent of the framerate drop depends on context. With an RTX 3080, when looking outside a car where the primary difference is RTGI and extended draw distance, there’s a significant 27 percent performance drop. When testing in a replay (where the extended RT reflections aren’t present), that performance drop in the chase cam view averaged around 16 percent. We generally recommend having the camera at this distance, as the cockpit framerate hits are high: in one shot we saw a 40 percent drop – keep in mind that full reflection coverage and RTGI can be quite expensive together.
In addition to the mod, we had some issues with the PC version of Forza Motorsport at launch, mainly due to CPU performance, which felt overly heavy and ‘spiked’. On a mainstream Ryzen 3600 we’d expect similar performance to the Xbox console, but frame rates were a little too high to reach a locked 60fps, while jumps to around 33ms could cause stuttering. Retesting this week, there’s a clear and welcome improvement: on average, there’s a 15 percent improvement in frame rates when CPU throttling. The boost will feel ‘better’, however, as frame-time spikes are significantly reduced. There are improvements on the GPU side too, although when testing on an RTX 2070 Super the improvement is only four percent, but still nice to see. It was also nice to see that the game now gives you clear and visible warnings if your settings are pushing you over the limits of your graphics card’s VRAM.
Overall, I’d say Forza Motorsport on PC hits a good point performance-wise. As for the ‘visual target’ mode, it’s clearly demanding on your GPU and has some visual issues, but I still think it’s worth checking out – but more importantly, there’s plenty of evidence here that Turn 10 could introduce a new ‘extreme’ graphics preset: improved detail and draw distance, improved RT reflections and RTGI would be great additions – assuming the bugs and denoising issues can be ironed out – if not for today’s mainstream hardware, then for tomorrow’s PC tech.