Which settings eat up most resources?

How do you feel is this game well optimized for smooth PC performance for those who have older machines? I found out that Resident Evil 7 can run at stable 60 FPS at 1920X1080 maxed out with SMAA on a Core i5 2400 3.1 GHz/GeForce GTX670 2 GB computer, with only shadows set on high, instead of very high. Sometimes FPS would dip to 50 though. What other settings eat up most resources?

Also, does anyone think that the setting "reflections" looks bad? I don't like it, i never seen such rendering and interpolation of reflections in any other game, i think this one was done not properly. Looks simply unrealistic.