Integrated/discrete GPU and memory

Discussion in 'MacBook Pro' started by Yoshimura, Nov 14, 2016.

  1. Yoshimura macrumors regular

    Nov 2, 2012
    For device with integrated and discrete GPUs, does the integrated GPU can use the graphic RAM?
  2. jackoatmon macrumors 6502a


    Sep 15, 2011
    the iGPU using the dGPU's vRAM ?

    is that what you mean?

    nah i would be very, very surprised

    defeats the whole purpose of the vRAM, which is it's right here on the chip with insanely fast bus speed

    or so my moderate level of understanding would lead me to believe
  3. mikeo007 macrumors 65816

    Mar 18, 2010
    The iGPU will only share system RAM. It does not have access to the GPUs on package vRAM.
  4. Yoshimura thread starter macrumors regular

    Nov 2, 2012
    Yes, that what I mean.

    This would prevent the iGPU to use the system memory as vRAM.

    Maybe the iGPU could still access it at a normal bus speed?
    --- Post Merged, Nov 14, 2016 ---
    So every time the system switches to the iGPU, the system memory drops?
  5. mikeo007 macrumors 65816

    Mar 18, 2010
    Not in any meaningful way. It will only use as much RAM as it requires, and any task that requires more than a basic amount of vRAM is probably going to engage the dedicated GPU.

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