FPS issues on XI are generally from software limitations, not hardware problems. It's probably dropping the frame rate because there's quite a few NPCs in that area, and it's also loading the other half of Southern San d'Oria when you're running from the mog house, and loading the mog house area (Lion's Square) when you're running from the AH.
Same thing with the texture joins. Nothing really that can be done about this.
Honestly, XI runs much better on older cards than newer ones. I have major artifacting issues on my Radeon 7770 on Windows 8, problems I never had on ye olde 9800 GT.
Edited, Jan 23rd 2013 11:16am by catwho