As for what supported means, it's the list of video cards that the game was tested on by EAxis. I looked up your card and the reason why it's not listed is because it's not a standalone video card like the ones listed as being supported. It's actually an integrated video chip on your motherboard. Usually these are on laptops but can be on pre-built desktops as well. I'd recommend getting one of the supported cards and more RAM (a bump up to a full 1GB will help your gameplay immensely). If you do get a new card, then get at least a GeForce 6800, if not something from the 7000 series. There's no point in getting a card that's too old because it won't serve you well in the long run with newer EPs and other video games.
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In addition - most of the reason why integrated chips aren't supported is that, while your game may run just fine now, it probably won't do in the future. IG chips aren't designed to cope with hard work, and after a while, they tend to die a slow and ugly death. Best to get a real card before that happens.
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