
Inside Apple's automatic graphics switching - soundsop
http://arstechnica.com/apple/news/2010/04/inside-apples-automatic-gpu-switching.ars
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soundsop
Interesting that the system switches between two distinct devices at different
power/performance points. There is probably some redundancy here, in that the
higher power/performance (discrete) GPU likely includes all the elements of
the simplified (integrated Intel) GPU. So the discrete GPU could be designed
in a way that dials down the power and performance to match the discrete CPU.
I know Intel and AMD CPUs include voltage/frequency/power-gating dials for
selecting a power/performance point, but I don't know if GPU engines make
heavy use of these features.

The simplified GPU being integrated with the CPU probably saves some power
from not having to go off-chip to talk to each other. This power savings might
be what justifies having two distinct devices.

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dedward
Most of us who bought the previous models were under the distinct impression
that a future OS upgrade would let us switch without logging in/out, and that
we could take advantage of the unused dedicated GPU for other stuff as well.

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mattparcher
I don't personally recall seeing anything to support this. Can you expand on
who/what gave you that impression, in case I just missed it?

The article suggests that this is both a hardware and software solution, so
that it would be impossible to add to older hardware not specifically designed
with these new techniques in mind:

 _"...because Apple is unique among PC vendors in that it controls both the
hardware and software."_

 _"NVIDIA's Optimus is another solution to this problem. It uses a combination
of hardware and software to enable automatic switching between integrated
graphics and a discrete GPU."_

More on Optimus: [http://arstechnica.com/apple/news/2010/02/nvidias-optimus-
is...](http://arstechnica.com/apple/news/2010/02/nvidias-optimus-is-primed-
for-new-apple-macbooks.ars) (indicating that it was a hardware-level
workaround required by NVIDIA's legal battle with Intel.)

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jrockway
What benefit do Aperture and Photoshop derive from the more powerful GPU?

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chadaustin
<http://www.google.com/search?q=photoshop+gpu>

