4k Realtime playback with more than 6 nodes?

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Jason Newfield

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4k Realtime playback with more than 6 nodes?

PostWed Feb 03, 2016 5:11 am

I just upgraded my Mac Pro 5.1, 6 core, with 42gb of RAM, SSD boot and media storage drives, OS X 10.10.5 and running dual GFX cards (Quadro 4000 GUI only and GTX 970 GPU dedicated) and am still only getting10-11 frms per second using 4k ProRes444 source material with seven nodes. Granted, there are a couple of layer nodes and a ofx on one of them and I have all the optimized options selected and I even tried caching the clips but still getting slow playback. My 970 is not flashed for mac but I have installed all the correct drivers and seems to be working just as it should expect for the fact that when I run playback, the 970 pegs its Processors but doesn't touch the memory at all. (monitoring on istats) Is this normal during playback? Isn't ProRes an optimized format for Davinci? I get a couple of frame loss when in 2k and full 24 firms per second in 1080 but really I want to color in 4k for various reasons. Is this possible at all with that many nodes? Do I just need twice the CUDA cores to get realtime playback with that many nodes? To be honest, I guess I expected more out of the 970, especially with ProRes. Am I missing something? Any help is appreciated. Thanks in advance.

Jason
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Jason Newfield

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Re: 4k Realtime playback with more than 6 nodes?

PostMon Feb 08, 2016 11:02 am

UPDATE: I ran some tests and found out that it is the qualifier node slowing it down. The node with the film convert on it slows it down by maybe a frame or two but the qualifier slows it down by 10-12 frames. Has anyone else had any experience with this?

Still hoping to hear from someone if it's normal that the memory on the GTX970 remains pretty much idle during playback and seems to be only using the processors.
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Rob Wentz

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Re: 4k Realtime playback with more than 6 nodes?

PostMon Feb 08, 2016 7:51 pm

Based on my experience You're not going to get realtime playback on 4k footage with more than 6 nodes with only one GeForce GTX 970. That card only has 4GB VRAM. You're stating "dual graphics cards" - but you really want dual GPUs your Quadro 4000 is being used (as you stated) as a dedicated GUI.

Also - As you've discovered of course it depends what those nodes are doing.

Based on real world experience - even if you have a similar system with dual titan blacks grading 4K footage you'll still run into situations where 6 nodes slow down playback.
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Jason Newfield

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Re: 4k Realtime playback with more than 6 nodes?

PostMon Feb 08, 2016 9:12 pm

Thank you for the reply Rob.

How about the processor to memory usage? I downloaded istats and it reads that during playback the 970 is using all of its processors but none of its memory... I assume that's the vram memory and the processors are the CUDA cores...? Is that normal functioning during playback?

My 970 is not flashed for Mac and I have heard tell that it could effect PCI speed... being 1.0 vs 2.0... ? Have you heard that to be true and would that make a difference on my Mac Pro 5.1?

I would love to have dual GPUs and I don't have Davinci 12 Studio and/or really the power to run Titans. I was thinking of trading my 970 in for a 980ti. I could possibly harvest enough power to run one of those and my Quadro for GUI.

Thanks again Rob.
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Rob Wentz

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Re: 4k Realtime playback with more than 6 nodes?

PostMon Feb 08, 2016 9:39 pm

Flashing the cards very well may improve your situation...
...or it very well could also lead you down a very dark long and winding rabbit hole.

It wasn't long ago I was noodling the same (expecting better performance on a mac from non mac flashed cards), but we went to Linux after apple limited the number of NVIDIA GPUs to two after os 10.8 was released. I couldn't tell you about what should be happening there with the memory on the cards via istats, but I also wouldn't trust what sw is telling you about the cards if the cards aren't fully compatible w/ the OS. . .

I was discussing the same option with these folks until 10.8 came out and we changed course due to the GPU limitation apple put in place. (in addition to the 2 titan black GPU cards we also have a Red Rocket X card which unfortunately "counts" as a GPU - :evil: )

Even still - Based on my experience here - in linux resolve w/ two titan blacks, RRX and Quadro k4000 as a GUI card - I wouldn't be terribly shocked to occasionally see non real-time playback in resolve when grading 4K footage with 6 nodes. again - it fully depends on what those nodes are doing.
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Jason Newfield

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Re: 4k Realtime playback with more than 6 nodes?

PostThu Feb 18, 2016 10:17 pm

Thank you for your help.
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brianbrook

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Re: 4k Realtime playback with more than 6 nodes?

PostFri Feb 19, 2016 1:24 am

Jason, try posting your Mac and GPU questions here: http://forums.macrumors.com/forums/mac-pro.1/
also MacVidCards can help you with questions about what flashing will get you with your particular system to possibly get more performance from Resolve.
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Dwaine Maggart

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Re: 4k Realtime playback with more than 6 nodes?

PostFri Feb 19, 2016 3:16 am

If you use Clean Black / Clean White in a qualifier node, that is very GPU intensive, and could cause playback performance issues on marginal systems. If that's an issue, would recommend node caching that node.
Dwaine Maggart
Blackmagic Design DaVinci Support
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Jason Newfield

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Re: 4k Realtime playback with more than 6 nodes?

PostFri Feb 19, 2016 5:42 am

Thanks Brian. Yeah, I have posted this question to MacVid and haven't heard back yet and I will definitely check out Macrumors.

Dwaine: Thank you for the info. I was trying to avoid caching due to processing time when making changes. Does that apply to just heavy qualifier selects? I often select skin tones only in a shot which need narrowed luminance and saturation blacks (not necessarily cleaned.) Would that have the same affect?

I have also posted a question about VFX and ACES work flow if anyone has any input on that.

Thanks again guys.

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