Ryzom

It doesn't mention lag in those notes. Has this been fixed too, or are they still working on it?

Its no replacement for content though. And certainly not for content that was promised at the time you bought the game. A mmorpg doesn't have to have a lot of static content to be worthwhile. Indeed I've found static content in the previous games I've played to be very limited (DAoC, SWG, AC2, AO ...

If your hard drive is thrashing away, that would point to more RAM as starting point. Certainly another 512mb wouldn't go a miss in your system, so I'd try that before going to the expense of new graphics cards.