GPU usage during Color's rendering

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Level 2

426 points

GPU usage during Color's rendering

According to page 322 of the Color documentation, "Color uses the GPU of the graphics card... to render the color correction and geometry adjustments that you've applied..."

I took a sample HD movie clip, imported it into Color, applied color correction and geometry adjustment, then started rendering. Using Hardware Monitor (which, among other things, measures the load on the GPU), I observed GPU load during the rendering process. The load never rose above 10% on our 17" MacBook Pro 2.4GHz unit.

We run a performance testing lab. Our clients want to know how much the graphics processor figures into the rendering in Color, Motion, and Compressor. So far, we can't find any function that stresses the GPU. The biggest load we've seen is when we do a RAM preview render of Fire Mortise 2 NTSC template in Motion 3 during which we see up to 40% load.

We're wondering if any of you can identify a function in Color that stresses the GPU. You can download a copy of Hardware Monitor at:
http://www.bresink.de/osx/216202/download.html

The latest, greatest Mac. Mac OS X (10.4.9)

The latest, greatest Mac., Mac OS X (10.4.9)

Posted on Jun 18, 2007 4:05 AM

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Answer 1

Jun 18, 2007 6:28 AM in response to rob_ART

Well, I don't know about benches that are able to see it, but in a MacPro, just switch the standard graphic card with an ATI X1900XT and you'll see that most probably Color is HIGHLY GPU dependent, as you'll see something like a 200% render speed boost...

Quite an empirical way of seeing it, but a reliable one 😉

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Answer 2

rob_ART Author

Level 2

426 points

Jun 18, 2007 7:32 AM in response to Jean-Luc Gason

That thought occurred to me. I'm going to try that next since we have a Mac Pro with the Radeon X1900 XT as well as one with the Quadro FX 4500. I'll compare render times to the GeForce 7300 GT equipped Mac Pro as well as the GeForce 8600M GT equipped MacBook Pro.

When I do the sample render on each machine, I'll monitor CPU usage using Activity Monitor and GPU load using Hardware Monitor. Plus I'll record elapsed time -- and report back here.

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Answer 3

fearless

Level 6

9,538 points

Jun 18, 2007 12:05 PM in response to rob_ART

Forget the 4500 - it's 8-bit only in Color. We've just dumped ours for an X1900 (2 actually, to share the load).

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Answer 4

rob_ART Author

Level 2

426 points

Jun 18, 2007 12:47 PM in response to rob_ART

I ran the same test on our Mac Pro 4-core 3GHz with the Radeon X1900 XT: Color Correction + Geometric Adjustment. When I started rendering, the GPU load never exceeded 2% (according to Hardware Monitor which samples the GPU load every 2 sec).

So I'm still puzzled by the documentation's claim that "Color uses the GPU of the graphics card... to render the color correction and geometry adjustments that you've applied..."

The latest, greatest Mac. Mac OS X (10.4.9)

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Answer 5

Jun 18, 2007 1:33 PM in response to rob_ART

I'd be more puzzled at Hardware Monitor's inaccurate reporting...

Patrick

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Answer 6

Jun 18, 2007 8:43 PM in response to Patrick Sheffield

I'd bet Hardware Monitor is spot on. The sort of colour transforms and geometry that Colour throws at the GPU are pretty lightweight compared to other GPU intensive tasks like 3D.

Toby

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Answer 7

Glenn CB

Level 1

5 points

Jun 20, 2007 10:41 AM in response to rob_ART

Did you try rendering in float? And how many color adjustments did you make? Maybe try doing a really complex ColorFX.

I'd love to see a barefeats article comparing Color performance on different hardware. Trying to decide if I should upgrade my quad G5 to the ATI X1900, I understand that it's not the same one as they ship with the Mac Pro....

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