15' MB Pro graphics questions.

Discussion in 'MacBook Pro' started by jtard, Jul 4, 2011.

  1. jtard macrumors newbie

    Jul 4, 2011
    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.
  2. jmmtn4aj macrumors member

    Feb 29, 2008
    It doesn't work like that. Programs can't use two unlike graphic cards in parallel. Even with SLI or Crossfire, where two like cards are used in parallel by programs that support it, the performance gains over a single card of the pair isn't even close to linear. Graphics performance ultimately has a lot more to do than the memory. VRAM speed and size only relates to the size of textures that can be cached by the card and the speed with which it can be written/read to and from. Depending on the program, the bottleneck might not be with the VRAM at all.

    If you want to find out how the two different discrete GPUs perform, google around for benchmarks run on those models.

    Both MBP models support switching, which means to save power your Mac will switch to the integrated, less power-hungry, Intel GPU. Under no situation will both integrated and discrete GPUs run in parallel, or even simultaneously.
  3. alust2013 macrumors 601


    Feb 6, 2010
    On the fence
    No, the MBPs have only ever been able to run one chip at a time. If you think you might have advanced graphics needs, the upgrade will probably be well worth it.
  4. jtard thread starter macrumors newbie

    Jul 4, 2011
    Thank you! That answers everything for me.

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