I'm thinking of getting a 15' MacBook Pro at some point after Lion comes out, and I'm not sure whether I want to pay the extra money to have the 1gb graphics card. What I'm wondering is whether or not the 256mb 6750M (i think thats what it is) in the base model runs parallel with the integrated chip when in demand (like some older nvidia ones did), or if it simply switches back and forth between the two. Also, if they can run at the same time I'm assuming the performance would be something like a 512MB dedicated card (albeit a theoretical combined ~700ish mb of graphics) considering the slower RAM of the integrated chip. Is that true? Thanks for any help.