Lag around Wall Prarie and Gokstad

[ByteMe]

I'm having terrible problems with lag around Wall Prarie and Gokstad. I can move fine leaving Birka and then when I hit the point of transition between lands, it just locks and becomes VERY unresponsive. To find one of the transition spots goto 915, 2114 and head South.

My video is ATI Mobility Radeon x300 under Windoze XP with the latest updates. I've tried with both of my users and the problem seems to be limited to me. The same account works fine in this area from the same machine running Ubuntu running the FGLRX drivers. Could it be a texture that's only loaded in this area? Gonna try setting my resolution to lowest to see if that helps...