It is mostlikely just the graphics card that is stopping it from running well enough on 1gig...although 1 gig is borderline in my opinion and 2 or higher is what you really want for sh4 preferably 3-4 if you want some longetivity for upcomming games.
Im getting a new system in about 2 months and I really cant justify spending money on a new card for this machine in the meantime, its just going to end up a MCSE study box for server OS's...
Im still surprised that the game runs asbadly as it does, it really doesnt scale very well, and I think Ubisoft are making a mistake doing this.
They are taking an already small market and making it even smaller with the harsh system requirements, alot of people wont go and get a new card for a game which scales 1024x768 with no AA. A patch to support other cards (as the box states) is too late the sales will have gone by then...
I think they will see an execive number of returns and less sales overall due to this and that hurts the series when the suits look at the numbers.
I am worried for this franchise, I hope Im wrong...
That being said Im going to return the game, untill I get my new machine, mabe it will be on special by then