Game experiences serious slowdown recently

I've been on break from FFXIV since the earthquake outage up until recently. Before I went on break however, my machine ran FFXIV exceptionally well on high settings. Now however, I'm experiencing graphical slow down which in turn lowers the responsiveness of inputs.

This slow down is most noticeable in any party size or 2 to 8. Where the frame rate drops below acceptable FPS and even the sound is distorted by the slow down. In plain, it looks like crap!

Even when solo running from place to place, inside a city or by myself in a zone, the environment lurches, which is also annoying.

What I really want to know is did a recent patch change how certain video drivers handle the game? Has anyone else experienced this problem recently? If so, how have you dealt with it?

My specs for anyone who would like to help:
i5 quad core processor @ 2.67 GHz
Windows 7 Ultimate 64bit
8 GB ram
NVidia GeForce GTX 470 (1280 MB GDDR 5)