Casual benchmarks
Thought I'd do a rough and dirty benchmark.
GPU: RTX 3060 (not Ti) (12GB VRAM)
CPU: Ryzen 5 3600
RAM: 16GB (DDR4)
Resolution: 1920x1080
Quality setting: Ultra
MC Idle
Looking at apartment, girl not in view: ~100 FPS
Girl from a distance: ~75FPS
Close up looking at girl: ~60 FPS
Note: MC movement does not noticeably impact FPS, the determining factor is the girl character's actions.
Sex scenes
Missionary on bed: 50-60 FPS
Reverse cowgirl: 45-55 FPS
Kneeling blowjob: 40-50 FPS
Misc
Outfit changes: 60-70 FPS
Spank/grope: ~60 FPS
Note: Results achieved by switching styles, speed, cum etc.
I tested D.Sim pre-alpha builds months ago on my 980, and when I turned most things off, I would get 45-50 FPS walking around and ~30 FPS in sex scenes. Not sure whether that has improved since then, as I no longer have the 980. I'll eventually test it on my 2070 SUPER, which should also outperform the 3060.
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I wonder how well my i5 12500k and 3060TI (and DDR4!) will handle this project? Probably fine, certainly not on ultra.
I would expect better FPS on your 3060Ti.