What causes -you- to lag?

[Chocobits]

But in all seriousness, CPU/GPU have no effect on lag whatsoever. This game runs on a pentium 3 with a geforce fx 5000 system with half a gig of PC 2700 ram like a champ, provided you don't try to go over 800x600 resolution. Try playing it on PC at 640x480.. you'll never lag again. It's called running the game on a PS2 emulator.

The only piece of hardware that is going to cause any type of noticeable performance gain for this game is an SSD.

And most people that have lag or crashing during specific times (certain spells/ja, cutscenes, zoning into certain areas), you need to set exclusions to the FFXI path in your security software. Antivirus/Firewall software is 90% of all lag not directly attributed to spaghetti code.