I'll give this a good go over the weekend and see how it performs.
Been having fun with this all morning, and it's a cracking looking game. Using a wet Bahrain I'm finding at 3840x1600 with everything up, DLSS quality is a difference of about 30fps on average, going from mid 50s to mid 80s. Makes a big difference, and I don't notice any visual difference in gameplay. May be little differences, but nothing I've noticed or care about.
Changing to DLSS performance makes another 25fps difference, getting around 110fps, and again very little visual degradation. Possibly some slight additional blurring as objects fly past, but it's minimal and if it means I could run this on a 3060ti at 60fps, I'd have it on in a heartbeat.
Running at ultra performance made the rain effects on the ground look like an epileptic nightmare, just random flickers everywhere. Performance was around mid 130s, but there is no way I'd be using it. It does note that it is meant for 8k, but I'd rather be lowering resolution or other settings than trying to make this work.
DLSS on, RT on
DLSS quality - Mid 80s
DLSS performance - Mid 110s
DLSS Ultra performance - Mid 130s. Awful rain lighting
The same tests without RT gave me this:
DLSS Quality - Mid 130s
DLSS Performance - More or less locked 140 (bouncing against refresh limit)
DLSS Ultra performance - Stuck at around 125, which seemed odd. Rain and rain refkections looked awful, little spots of random light everywhere, tarmac, ground... Just really bad.
TAA Only - Around 100.
Its a game where RT looks good in motion, but as previously noted probably the least useful RT in game. Looks great for benchmarking, but ultimately will not really draw the eye when you're actually racing. DLSS is a big aid here, but don't use ultra performance in the wet unless you like the impression that an over enthusiastic DJ is in charge of lighting.
FSR tests, RT on:
FSR quality - Around 90fps
FSR performance - Around 115fps
FSR ultra performance - Around 130fps
FSR tests, RT off
FSR quality - Locked 140, refresh limit
FSR performance - locked 140, refresh limit
FSR ultra performance - Locked 140, refresh limit
On the whole FSR (except ultra performance) doesn't do a bad job, and for this game I'd definitely be using it for increased framerate if necessary, but there are a few points even on quality settings such as water spray coming off rear wheels doesn't look right, and sometimes (not always) fences are just smears as they go past.
FSR ultra performance looks terrible, almost as if no upscaling has actually taken place (exaggeration, but still...). No definition on anything in motion at all. I would easily be turning other settings down or off before resorting to this. Same caveat as DLSS above though, meant for making 8k playable.
In summary, Ray tracing at a high level does improve visuals in this, no question to me. But unless you have a high end gpu, the upscaling is more important. Both options work here, and I would favour DLSS, but FSR is fine as long as you go no lower than balanced. Performance does work, but you really start to see the difference here.