Hi,
there is some issue with DLSS.
I turned on DLSS on quality, do one race, after that i enter to garage to tune car.
After all that i back to options and saw that DLSS just dissappeard and FSR just apper 
Normally i did not have FSR in graphic menu.
Also cars in garage when tune them or painting has really low resolution ? WHY.
Graphic set to ultra, render scale 100%, resolution 1440p or 4k with DLDSR.
Graphic card is RTX 4070.
same here , few races no problem 60fps next race 28fps no dlls option , just gone forcing a restart
same problem
DLSS isn’t working properly for me either. I just turned it off. I’m seeing little to no benefit with occasional stutters. The game is smooth without it for me.
Having this issue when using dlaa
Same issue here too. Just drops DLSS after one or two races.
Same problem here to dlss turns into fsr. I do still run at 60fps tho
I have the same problem.
For me, it definitely happens when I go from the lobby to my car screen, then to the paint search page and back to the lobby.
The FPS suddenly drops, and when I look at the settings screen, the “DLSS” item disappears and it changes to “AMD FSR.”
When this happens, you have to shut down the game and start it up again to get back to normal.
I hope it can be fixed soon …
OS:Windows11 22H2 22621.2283
VGA:nVIDIA GeForce 4070Ti
VGA Driver:GeForce Game Ready Driver 537.42
same here, 4070 ti 
Same here with a 3070, starts okay with DLSS on then after a race or two it’s off and I have the FSR option instead.
I see this is common issue.
Need to be fixed asap
did a few test and the game runs smoother 60fps with dlls off , seems that dlls has zero effect on this game , maybe because there are no nvidia drivers for this game yet . game runs great now 9900K & 3080ti 4K max settings raytracing on auto settings .
bumping the post, this should be fixed asap, additionally dlss doesnt seem to do much, so mabye its not working for me at all. (rtx 3070 ti)
Same issue, R7 5800x, 3080 10GB
For some reason on my PC running a RTX 3070, NVidia DLSS randomly shuts off and is replaced with AMD FSR which……doesn’t work for me. So some times the game will run super smooth and then when it switches it runs ugly and at like 12 FPS.
Wierd
Yep, I had this also.
You beat me though; my 3080 dropped to 9 FPS. Why is your 3070 33% better at FSR2 than mine? 
I bought on steam and if I open the game in desktop shortcut its open with AMD FSR but if I open the game in steam library its open with Nvidia DLSS… Btw DLSS does not worth to open I already tested and its only gives 10+ fps when pick balanced. You need to optimize your settings I’ll share my video check this one ;
Best Graphics Settings in Forza Motorsport 2023 - Best Quality with Max Performance 4K - YouTube
Yes DLSS does not effect to game its only give %10 fps when you pick balanced and its not worth it. For me if I open the game shortcut on desktop (bought steam version) its open with AMD FSR and if I open in steam library its open with DLSS… wierd. Btw you can check my optimized graphic settings with 3080ti you can get more fps with nice graphics.
Best Graphics Settings in Forza Motorsport 2023 - Best Quality with Max Performance 4K - YouTube
Start tutorial 3 races with dlss is ok around 60 FPS in 4k on ryzen ,5950x with 3080 ti
After tutorial next championship practice run a 12fps.
Strange… info in vidéo paramètres, dlss is not present only fsr2 ( not selected)
Windows 11 french version with last update (10 october)
even after the new nvidia driver update for Forza DLLS is still broken worked 5 minutes 60fps then bogs down to 20fps . back to turning it off again .