not quite ... the i810 implements what looks like an AGP VGA with no memory of its own, everything borrowed dynamically from system RAM. On top of that, there's a constant 1 MByte set aside to emulate a minimal set of legacy text and graphics modes, for use in operating systems that don't have native drivers for the i810, and of course during the initial boot phase.
That 1 MB cannot be increased ... but that doesn't matter anymore once you have native drivers running. Then, it'll borrow as much as it needs anyway. Limits do exist however - memory bandwidth and pixel clock ceiling are limiting the thing to low color depth and resolution.
If a game is silly enough to insist on a certain amount of graphics card local memory, then you're busted. Games aren't supposed to do that at all, since the "borrow system memory when there's not enough graphics card memory" is the whole idea behind the AGP concept.