Why does Wet / Night racing absolutely CRUSH my VR frame rate

I understand that having a wet race OR night race will impact frame rate and it is probably more noticeable in VR due to the stereoscopic rendering (not just resolution), but it seems somewhat excessive.

I setup a race at Spa starting first in a grid of 20 GT3 at late evening (19:00) and whilst I have pretty high settings with MSAA Medium (SteamVR SS 130%) I can maintain a full 90fps around the entire track. No stutters, constant frame rate.

If I just set the exact same race to "Rain" starting on "Wet" track, my frame rate goes down to 45fps with downhill straight sometimes dipping into the 30s (first lap). This seems ridiculous. I can turn MSAA off, reduce my Super Sampling down to 80% (reduction of 50%) and its still in the 40s at times. This is a frame rate degradation of over 50%. There doesn't seem to be any setting that magically fixes this issue.

Is this ever likely to change? Its pointless even trying to tweak for these conditions being as the frame drop is so unbelievably large when compared with dry conditions.

EDIT: Even Turning all settings down to LOW or OFF doesn't seem to allow me to get to 90fps (Still sits at 45fps on start line). Seems very odd to me.

 

Looking at your PC system the impact seems excessive.
But thinking about the rendering of the double amount of as example raindrops at least I (moi) think its understandable.
But still irritating I admit.

ByTheWay: My guess about why we dont have VR sets at the moment that is comparable to the display quality of good 4K monitors is that no affordable PC system would be able to feed it in the next (lets say) 4-5 years. Just think about the system Pimax announced 12K set would demand.

 

I have the same issue in triples, though I get back up to my 60FPS when the field has spread out a bit after the first lap. It's straight sailing from then on. At the start I'm somewhere between 40-50 FPS. Interestingly, adding rain to a night race doesn't influce FPS any further, but adding night to a rainy race does.

I imagine rain hampers FPS due to surface reflections and night due to many many light sources that all cast shadows.

BTW I have the same phenomenon in ACC, so I guess it's not something specific with the Madness Engine. Hopefully Reiza can squeeze some performance out of nihgt/wet races.

 

It used to be much less of a hit before the November (?) patch. Something changed in shadow and/or reflection rendering which is not visible in quality but killing fps in those conditions. Reiza have still not answered.

 

Can you give me a scenario to test please that drops down to 40 fps? Lowest I've seen so far is 74fps in my testing!

Mind you, I don't do much night driving in AMS2 because of the awful shimmer, (seriously the worst shimmer I've seen in a game with AA) so I guess I haven't done a huge amount of night/rain testing, but when I did it wasn't 40 fps. But I would like to see how bad it can get and also see the CPU differences.

I do a lot more night driving in ACC and do love me some rain but I have not seen lower than 60 fps there though. I run almost all maxed out except mirrors and I have resolution scale to 120% just to keep the GPU loaded as I see much higher CPU demand in ACC.

 

Yes I remember reading in 2 different patch notes that shadows where improved, but did not notice any visual change, still low or ultra shadows look awful! Again, the worst of any game imo. Dam shadows and night shimmer really destroy the otherwise great image!

 

Performance isnt to bad at night and rain in this quick test! Is there any specific combination that is worse?

Getting full use of the GPU which is good.

I realise this is a VR topic but just stating performance is only dropping 25 fps for me here from clear day running in triple screens! It may just be a VR thing.

 

I think AMS2 (tracks) need to be still optimized because the fps loss is track-dependat and it is higher than PC2

 

It's probably my settings tbh. I run all my graphics settings at their highest possible settings and have to use VSync since my monitors are crap and tear a lot. I use MSAA, but there is no difference to using SMAA performance wise. Supersampling kills my FPS even at day without AI. I also use a reshade mod that takes 10-15FPS, but interestingly disabling that doesn't really help at night time. Since FPS only drop with night time race starts, which realistically only happen in the Bathurst 12 hours anyways, and any other scenario runs buttery smooth 60FPS, I find it unreasonable to turn the graphics down tbh ^^

My go-to test scenario is Nürgurgring Veedol, night time (say 02:00), a full field of GT3s (that's 29 AI), starting in the middle, somewhere around 18th. Rainy weather, wet track. For me, FPS drop between 40-50 until I'm out of the Stadium section, and maybe go down to 55 again when I'm back at the Stadium, depending on how well I'm doing. There are no more drops after that. I use Nürburgring because it seems to be one of the more demanding starting areas.

 

I decided to lower the second reflections to medium, track detail to high and mirrors to not the higher settings, the rest maxed out also including MSAA high. With these settings I gain a good chunk of frames with next to no loss in visuals.
My biggest reason for my upgrade to the 3080 was for G-Sync across triples and having higher fps is also amazing. If i was you I would lower those couple of settings i mentioned as you will gain performance with a not even noticeable loss in visuals. I also have reshade installed on my main AMS2 but always switch it off now as I think it looks a bit worse for a hit in performance but that is a personal preference.

 

I'll try that and see what the difference is, thanks I forgit to mention that shadows are already on high, not ultra.

Better monitors are on the very top of my simrig upgrade list

 

To me shadows can be on low or ultra, make very little difference visually, I forgot also, they are on low also.
I got my monitors back when I had the 1080ti thinking I could do triples G-Sync but Pascal can only do G-Sync on a single. Previously I had just 1080p 60Hz triples.

 

I'm guessing that at night, each set of car headlights and track-side lights becomes its own light source and therefore creates its own set of dynamic shadows, ambient occlusion parameters, etc.
The system has to account for all of that, whereas during the daytime, the solar light source is the singular and dominant one, with less apparent stress on the system?

That's my very loose understanding of it anyway!

 

Speaking of headlights at night, i reported this and devs are working on a way to help here! This is a place i do notice performance issues and it is directly related to these lights passing under the barriers.

 

I tried your settings and did play around with them a bit. In my usual test scenario (Full field of GT3 @Nürburgring), when starting at night without rain, setting shadows to low already gives me steady 60FPS. If I add rain, I also need to use your other settings, but if I don't it doesn't actually drop that far and stay around 55 FPS mostly. Track detail setting did not change FPS for me in any scenario btw.

I found another scenario that appears to be heavier on the system, I dropped to 50FPS on the first lap even with your settings. Maybe you could try it some time and report your findings. GT Classics at Imola '88, rain, 1st of may 1988, 07:00 in the morning, full grid, start around 20th on the grid. The same as before, as soon as the field spreads out after the forst lap even with all the spray I get steady 60FPS again, but the first lap is really heavy on the system. Maybe Imola is badly optimized, no idea.

 

I will test that scenario some time today and post back my results. Was it just rain and real time transition?

 

Yes on the grid im getting 58fps

but by pit exit im at 67fps

and as im mid the first big left bend im at 78fps

then it stabilises to around 80-100 fps as the field spreads.

the God rays are nice at this time

 

Yeah it's a beautiful setting to race in, especially with those cars Those are way better FPS than I get btw. I get dips below 60 around the first lap in several places, but I also remembered that I didn't disable my Reshade to test the difference. VSync may also make the dips seem more severe than they are because of how it works. It could also be your CPU.

I see another testing session in my near future

 

I think something has changed with CPU load recently, too.
Did some tests with fpsVR and had lots of spikes (on TT!), once again a bit track related, but it was more or less on every track I've done tests.

I could really feel that frametimes are not smooth in my VR headset.
Remembering there were some issues in the past with the Default+ FFB Profile, but change back to Default didn't help anything. Also tinkering around with UDP Settings didn't do anything noticable. Not sure if it is once again something related to the documents folder, maybe I should try resetting that again. Pretty sure, the game was by miles more fluid in the past, I could easily drive Nords without any issues - now I feel there is something wrong on some places.

Sitting on a 3700X CPU, so this should not be too big of a problem.

 

Same and running a 5900