I benchmarked my installation, Vividian ENB (default vanilla preset) together with Vividian Clouds and Groundfogs, VividSnow, Climates of Tamriel, Supreme Storms and Enhanced Snow System took me down from 56.3 to 36.0 fps (while reducing VRAM usage and improving fps stability quite a bit). As CoT and the others are known for having a fps impact, the effect of Vividian wasn't that bad.
Why aiming for 60fps+ anyway? Are you planning to use Oculus Rift?
Thanks for the tips (& you too TechAngel)
to answer your question~: first 100~120 / 57 % = 43 ~ 51,6
so yeah I'd prefer 60+ but anything about 50+ is fine, 45+ is tolerable
and why aim for that, well it's a question of personnal preference on the responsiveness of games, 30 FPS games tend to annoy me to no end, and a 45 average means you'll get some dips to 30 already. I already played in conditions like these on multiple games before, I can get accustomed to it but I don't like it.
For example a little while back I had a GTX470 superclocked (approximately equivalent to a GTX560Ti), and Tomb Raider 2013 was running not so good, so I disabled some stuff but still left the tressfx effect, because I felt like it somewhat increased realism (even though sometimes the wind direction for your hair seemed wrong), I had to bear with the 30~45 range FPS for playing this, I did it but didn't like it.
I can't really explain this, it's a general feeling, I know most people are less sensitive about this than I am.