poor framerate ONLY in a hubs.

[rattt]

Where im inside a hub such a Santa Monica or Downtown my framerate is very i mean VERY poor (especially when im starting to look up).Inside any location everything works fine (about 30 - 40 fps).What is the problem?
XP 2000+
ATI 9000
512 RAM

[Luciel]

try reducing the resolution or setting the graphs to a lower level