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Windows does not use GPU, Mac does

PostPosted: Fri Jan 10, 2020 6:51 pm
by Roman78
Hello everyone.

I was wondering about the best configuration to edit videos just for hobby. So I installed Davinci Resolve on my older 2010 MacPro. That is running quite good, but I noticed the CPU just get 30% utilization. A 5 minute Video 1080P 50 FPS takes about 6 Minutes.

So I read a little and I discovered that the GPU does the most work. On the MacPro I have a GTX 680, this one has no hardware H264 or H265 Support. On the other side of the desk is my Gaming Computer, an i7-4790K with a RX480. That one has hardware H264 and H265 support. So I installed Davinic on there. The same 5 minutes Video takes double the time. And I discovered CPU is running on 100% and GPU on 0%.

So somehow Mac does us the slower GPU and not the 12 Cores of the CPU. On the other hand Windows does it just the other way around. So I suppose I miss something on my Windows Computer? OS is Windows 10 indeed.

Re: Windows does not use GPU, Mac does

PostPosted: Sat Jan 11, 2020 4:29 pm
by Jim Simon
The difference isn't between Mac and Windows, it's between nVidia and AMD.

nVidia is better.

Re: Windows does not use GPU, Mac does

PostPosted: Sat Jan 11, 2020 8:37 pm
by Uli Plank
The hardware support is free under MacOS, while you need the Studio version for PC.

Re: Windows does not use GPU, Mac does

PostPosted: Sat Jan 11, 2020 10:11 pm
by Mike Manus
Did you check preferences>system to make sure the gpu is enabled?

Re: Windows does not use GPU, Mac does

PostPosted: Thu Jan 23, 2020 12:28 pm
by Roman78
Thanks for the Support :D

Jim Simon wrote:The difference isn't between Mac and Windows, it's between nVidia and AMD.

nVidia is better.


Interesting, on a MAC Nvidia is out of support. The last Mac containing a Nvidia GPU is the 2013 iMac. On Mac they go the AMD-Only way since then. Also the AMD has hardware H264 and H265 support and the somewhat older Nvidia GTX-680 does not.

Uli Plank wrote:The hardware support is free under MacOS, while you need the Studio version for PC.


Hmmmm that would prefer the Mac Way. Or sell the MacPro and buy Resolve. Hmmm or just buy a Vega for the MacPro.

Mike Manus wrote:Did you check preferences>system to make sure the gpu is enabled?


I'll will have a look at that.

Re: Windows does not use GPU, Mac does

PostPosted: Fri Mar 06, 2020 6:34 pm
by Roman78
So, i had some time to play some more.

I experimented a little with the settings, but it won't use the GPU for encoding. The RX480 has hardware h264 and h265 encoding build in, but somehow it is not working with Davinci Resolve. I can not select any option for this, I can only select Auto-OpenCl-CUDA (and cuda is NVidia as I just read).

So is it possible or not to use hardware acceleration with the free version on a AMD GPU on Windows? Or is it better to use Nvida on Windows. Does Davinci support hardware encoding in the Free version? Or should i use the MacPro and get a better card for that?

Re: Windows does not use GPU, Mac does

PostPosted: Fri Mar 06, 2020 6:48 pm
by Sulo Kokki
If you can, throw a Vega 56 into your Mac Pro.

It's better value than the 64 model and will give your system a huge boost, guaranteed ;)

Re: Windows does not use GPU, Mac does

PostPosted: Fri Mar 06, 2020 6:55 pm
by jasonvp
Sulo Kokki wrote:If you can, throw a Vega 56 into your Mac Pro.

It's better value than the 64 model and will give your system a huge boost, guaranteed ;)


If encode/decode is the performance bump you're after, I'd look into something Navi-based like the 5700XT instead. Navi has a much newer hardware encoder/decoder on board that's vastly faster than the older-gen AMD cards.

Vegas are great compute cards, but their hardware encoders/decoders are a generation or two behind.

Re: Windows does not use GPU, Mac does

PostPosted: Fri Mar 06, 2020 7:04 pm
by Sulo Kokki
You sure?

Every Davinci bench I've seen for Navi has been a disappointment. I recall seeing the macOS Navi/Vega encode benches at Barefeats, and was surprised to see that the 5700XT was almost as good as Vega 10/20. This was a surprise, as the noise reduction, Fusion et al heavy process benches at Puget (on Win?) had shown Navi get hammered by all the Vega's, Turings and higher-end Pascals.

Just now AMD said they're branching their GPUs to gaming (RDNA, the cheaper Radeons) and computing (CDNA; the Vega successors). Means the gaming GPUs are and continue to be a bit rubbish in Resolve, next to the Pro models, which are likely to feature HBM2 memory. This reflects on their market share and price, which is a bit bleak.