So I just tried this circuit not long ago and encountered a somewhat strange performance issue. When doing practicing with 11 ai cars, if it's a single model class (such as the 911 GT3 cup), everything appears fine, acceptable fps drops (from 75 to 58 ish) in certain places (mainly when facing the hill). However if it's a multi maker/model class (WTCC 2020 for example), the fps drop is just insane, from 75 to 30 ish in the same places. I've never had any issue like this on any other tracks in the game. My setup is 10700k 3.8GHz, 5500XT 8GB, 32G RAM and SSD. Monitor is 34" ultra wide at 2560 x 1080, 75Hz. FYI other sims I play (Dirt Rally 2.0, Assetto Corsa) all run flawlessly with mix of medium to ultra settings. I tried to play with the graphic settings in R3E and even set everything to lowest, it doesn't really improve this weird issue.(boosted 5-7 fps max). Unless I run with 0 ai cars. Anything more than 3 ai will make it a slide show in those places near the hill. Anyone encountered similar issue too? I'm thinking maybe the track is just not well optimized.
Same issue here when running with a tight 15 AI pack, albeit with a much slower cpu that usually keeps 60fps everywhere else, and under fairly med-lowish cpu-load related settings to overcome that bottleneck. (fx8350@4.5,16GB ram,RX480 GB) There's probably some draw-call heavy sections requiring more optimization to match other content, as when approaching and after t6, sometimes by t13, and in the last section after t18 where most fps dips seem to happen. Specially during L1 while the AI grid is still tightly packed close ahead. So, having a single-make grid could be helping greatly to reduce draw calls, as the tracks' geography can give a far view to a lot of stuff on screen. In my system vs. a grid of mixed WTCR 2020 cars performance suffers, but less vs. a similarly sized grid with only one of these cars (or any other proper single make series I've tried, like m235iR, Cayman cup or Cupra e-Racer). It's a difference between 45-54 fps slowdowns, vs. keeping above 65fps in similar situations.
T3 and the back straight i get some frame drop, the chinese tracks in general (theyre also quite new) are seeming to be harder to render, there was genuine problems a while ago with them but thats fixed now, they just seem to be more taxing