I 'fixed' my issue with new drivers, and I play on Normal, to get frames of around 80+ mostly, but premium is absolutely unplayable

Why bother having it at all in this state?
I've been asking for a Vsync option, as it being off significanly reduces mouse lag (essential to have low for this game), and increases performance.
Dylan, anti-aliasing and resolution make absolutely no difference at all. I've got mine set to 1920x1200, and 8x aa, and it impacts maybe around 1 or 2 frames? It's obviously a coding issue.
EDIT: I'd like to know what you did with the latest patch, as I can now play Enhanced without being annoyed by lag again! Finally I can see those lines after beats again! This patch does seem to have fixed the majority of the problems, and even premium is playable, although only just. Well done anyway!