Sylwester Pietrzyk wrote:
Adam Maas wrote on 14.03.06 14:15:
Quartz 3D in Tiger uses the GPU for almost all graphics (For example,
Quicktime 7 plays back on an OpenGL surface), and Aperture actually uses
the GPU for a lot of the basic image editing calculations,
For what? What 3D operations does aperture do to 2D pictures? Please don't
tell me that GPU is used for image editing, because it is not true. Yes,
there were specialised graphic cards for Mac that had dedicated CPUs
accelerating many photoshop filters, but it was back in early nineties and
won't probably happen again. GPUs used in today's cards are used solely for
3D operations acceleration and won't accelarate image editing calculations.
Everything in the Tiger UI is rendered on a 3D surface if Quartz 3D is
enabled. Aperture offloads calculations onto the GPU as well, using the
Core Image framework and Image Units(Which is an accelleration
architecture designed to take full advantage of the processing power
sitting unused in the GPU). Core Image essentially uses the floating
point speed of the GPU to massively accellerate 2D calculations. The
other advantage is that Core Image can do parallel processing of said
calculations, using the SIMD units on the CPU (Altivec and SSE2 on PPC
and Intel respectively) as well as the GPU.
Here's a good overview:
http://developer.apple.com/macosx/coreimage.html
so it requires a hefty GPU with lots of VRAM. Apple has tried to offload as
much as possible onto the GPU, which means that performance on machines
with only 32MB of VRAM is adequate at best. Aperture actually mentions
GPU requirements in the minimum system requirements (IIRC it's a Radeon
9600)
If lightroom can run just happy on much lower spec Mac with Quartz enabled
graphic card I can't see any reason why Aperture couldn't. For me it is
rather Apple's politics to convince pro photographers to buy a new Mac.
Because Lightroom doesn't use Image Units, Aperture does. Making
Lightroom far less dependant on GPU performance. Lightroom performs much
better on low-end hardware, while Aperture really shows off what the
high-end hardware can do, because unlike Lightroom, Aperture can take
full advantage of the increase in GPU power.
-Adam
