Textures not Loading. Looks like a Disco [PC]

Computer Specs:

Ryzen 1600, Overclocked and liquid cooled.
Vega 64 Liquid Cooled, Overclocked.
16Gigs FlareX 3200 ram.
Msi X370 Mobo
250gb M.2, 500gb SSD
1000w PSU gold.
3440x1440, 100hz monitor.

Randomly surface textures wont load in some areas, causing a disco like effect during races. Immediately after driving into the disco, brightness drops and eventually comes back up to normal after a few seconds. I don’t think my PC is the problem… Gpu drivers up to date 17.11.3, mobo bios current also. PC is more than capable to run this game on Ultra in my resolution and still be above 100fps. this has been happening since early access. I also still get a slight hitch or studder here and there.

Had the same issue while playing yesterday. I also have a MSI Radeon RX Vega 64 Liquid cooled card. Running on a i9-7900X 32GB of RAM. Graphics card is at stock speeds and runs on a 144Hz 32 Samsung freesync 2 monitor.

I see these rainbow flickering textures as well and screen darkening at times. I’m going to try and run a repair on the game and also do reset of Shader Cache in AMD drivers and run disk cleanup and delete DirectX Shader Cache and see if that might be the cause.

Ok for Vega users this is a known issue I guess, just read it in that thread. See fix, I did this and it works fine, just turn on the HBCC setting go to AMD Radeon Settings control panel then Gaming → Global Settings and turn on HBCC by checking the box, set the RAM setting all the way to the left (lowest amount) you can use more if you want of course just keep in mind how much overall system RAM you have. I verified this fixed the issue for me in both Forza 7 and Forza 3 Horizon with 17.11.3 hotfix drivers for Vega cards.

• Players using AMD Vega hardware may experience graphics not loading properly on the track when racing. We suggest enabling the HBCC Memory Segment by opening the AMD Radeon Settings app and going to the Gaming tab → Global settings and clicking the “HBCC Memory Segment” option. Make sure the slider next to the setting is set all the way to the left. Players may also see the screen go black or see flickering for 1 minute after turning on the setting.

Full known issues thread here, its at the top Forza Motorsport 7 Known Issues [PC/Xbox] - Community Support - Forza Motorsport Forums