I did another testing, now properly, in the morning I didnt have time before work to do anything extensively.
I saw a VR video of rf2 in 90 fps and wondered what might be behind issues,
it might be weird, but ISI content runs very smoothly, it is actually the biggest surprise Ive had so far. 100 fps with full graphics and 13 AI on track: nice

). However rain drops this fps by a double (50 to 60)
At night it is okay, plus I tried to do some racing. It looks very nice
The problem begins with non ISI content.
In the VEC VLMS league, we run our cars I believe from URD and the fps stays with the same details at about 45 on la Sarthe, but in rain condition it drops to 21 :O.
Smoothness and resource wise: it is amazing. I think it just lacks a bit optimisation here and there, but generally I have a great impression