FFXI is SUPER crazy Lag in win7 GTX260!

Details:
I installed Final Fantasy XI, to start the game, the game screen intermittently freeze, about every 2-3 seconds will stop half a second，the game looks like a hiccup。

Steps:
1.The opening CG has begun to intermittently pause，Go to Start menu, the background the bird's-eye views of the same intermittent pauses, trees and stones of the ground, the distant terrain read seems to have a problem, every 2-3 seconds into the game, the screen stops half a second, even ifthe figures do not move, the picture is intermittent pause
2.I try disabling HID devices, but does not have any effect, the game is still intermittent pause
3.I try to modify the resolution in the config program, but regardless of 1440X900 or 1024X1024, regardless of window mode or full-screen mode, still intermittent pauses
4.I try to install the old version recommended graphics driver 266.58, but still does not have any effect
5 Some reason I live in China, the network type is ADSL 2M-bit (slower)
Date & Time: Always
Frequency: Always
Platform: PC
PC Manufacturer & Model Number: Homebuilt Computer
OS: Windows 7 Ultimate
Graphics Card: NVIDIA GeForce GTX 260+
ISP: China Unicom
Type of Internet Connection: ADSL