The Cyseal marketplace is probably the most demanding region in the game (with the number of NPCs and items around, NPC scripts, the fountain water effects, etc).
An 'old' save shouldn't make a difference, I don't think. The game itself has not been updated since before the EE came out, so it may be the most current, anyway. Even if it was started in an earlier version, I don't recall any performance issues that required starting a new game to address.
