Major stuttering issue

[RAIST]

I must of been tired, can't believe I forgot that.

OS: Windows 7 64-bit
CPU: intel Core i7, 950 @3.07 GHZ
GPU: Asus GTX 560 ti, latest drivers
RAM: 16gb
Network: I'm with TalkTalk, which I doubt helps, but I've opened up all the ports and given it free rein to go through the firewall. Wifi Connection

All drivers are up to date to my knowledge.

This may be a large part of your problem. FFXI is notorious for having issues with the newer cards/drivers. It's been tested against an older driver on the 500 series, might want to try the recommended drivers (after a full driver cleaning, to avoid any mismatched versioning on the DLL's).

WiFi can be a bit iffy too....sometimes it can inject a spot of lag, but that's hit and miss depending on varying environmental factors. I'd look into driver issues first, as that is a common problem with older DirectX games in Vista/Win7. There may still be an active thread on the issues on the nVidia Forums in the 500 series GPU section.