The PotBS developers are working to address lag issues for players using the Windows Vista operating system:
We believe that we have discovered a work around for Vista users experiencing lag.
It appears that the conflict revolves around the way Vistas TCP stack resizes its receive window for large amounts of data, contributing to lag issues. Customers that have taken the following steps report successful resolution to the lag problem.
Here's what you do:
1. Be logged in as a user with administrator privileges
2. Open up the start menu, go to All Programs > Accessories
3. Right-click on the Command Prompt icon and choose Run as Administrator
4. Type netsh interface tcp set global autotuning=disabled
5. Re-start Pirates of the Burning Sea if its running
To turn the setting back to normal, follow steps 1-3, and type the command netsh interface tcp set global autotuning=normal
Let us know if you should continue to experience lag issues, or if following these steps resolved this issue by posting to this forum thread.
Many thanks to the folks who helped us troubleshoot the problem, and our apologies for any inconvenience this may have caused!
Sounds like a "doable" solution. Good luck!