FPS stutter

[Nyarlko]

What's your CPU/RAM look like when the system is totally idle? Try adding up the percentages being used reported in Task Manager. If there's more than ~10% unaccountable for, then odds are it's Windows itself acting up. If you have significant activity on more than one CPU while FFXI is the only program up and running, that's also a pretty solid sign that it's not FFXI causing the issue since it is not multithreaded and is mostly stuck in a single core. It's quite possible that you have a Windows Update getting downloaded, or Windows Anti-Malware scanning your system, "in the background" which is hogging your resources and blocked from users' eyes. Should be illegal, what MS gets away with forcing down our throats.