Playing on 450Gts and let me tell you i can play on pretty much high setting i even try depth of field and amient occlusion not at the same time but you do get a 25-30fps in the city and 40fps outside not too my liking so i dont have any of them on.

i just try a new setting and pretty much am getting this

Window size 1440x900
multsampling 16xq CSAA
genereal drawing quality = 8
Background drawing =5
Shadow=high
texture quality=high
Texture filtering=highest

I even have everything on within game shadows and the other setting and i don't see any type of lag just the lag the same lag i would get if i had everything on standard.

So ya ffxiv need to be better optimization even if you play on the lowest setting you have lag within city which is a joke to me.