question bout graphics cards using ram

hi i was wandering if someone could answer my question please.. if i have 1 gb ram and i get a 512mb vid card then does that mean that i now only have 512 mb ram? does the vid card give u more ram or take it from u? i kinda think it gives u more ram for when i installed my 256mb 8400 gs and i ran dxdiag it showed me as going from bout 960 mb to almost 1024mb.

Your total system RAM stays the same when you install a new video card. Like Stoner said, it's dedicated. The change you saw when you installed the 8400 gs was because your integrated card was using system RAM, since it didn't have any of its own. Your computer always had 1024mb, the integrated video adapter was using 64mb of RAM to power itself. But, now say you install a 512mb card, you won't see your system RAM go up anymore, because the integrated card isn't drawing from it.