Yes, the
total amount om memory is 512 MB but it's 256MB XDR RAM and 256MB GDDR3 VRAM. I beleive the second set of memory is dedicated and restricted to the GPU.
In any case; If you're a game junkie looking for yet another fix I agree that the lack proper support for the graphics sub-system is a bigger problem than the lack of memory. But if you're a dry scientific dude in search for some raw number-crunching and with an explicit interest in parallel computation you don't really care about that. Then the lack of substantiell memory, say at least 4 GB, is a far more serious issue. Guess I'll have to wait for cell-based blade-servers from IBM instead of this toy! :-/