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Improving render performance

PostPosted: Tue Jan 14, 2020 5:02 pm
by Pixelslayer
I recently got a new laptop that I thought might do a passable job of video editing, but it seems to be fairly poor at the job. Well, at least at rendering output. Here are the specs:

Dell Inspiron 7586 2-in-1
i7-8565U (4 cores, 8 threads)
Nvidia MX150 GPU (2GB VRAM)
Intel UHD 620 integrated GPU
16GB DDR4-2400 dual-channel RAM
512GB NVMe SSD
15.6" 4K screen

I know the MX150 is pretty much the bottom of the barrel as far as dedicated GPU's go, but I thought it would be noticeably better than integrated graphics. However, an 11 minute 1080p video clip (Youtube preset) exported in 25 minutes. No advanced effects here, just 3 or 4 simple text titles and some cuts of the original material. The original source is a 3 hour 1080p h.264 clip recorded at 15Mbps.

Is there anything I can do to improve render performance (aside from getting a new laptop)? Looking at Windows' performance monitor, I see that when rendering Resolve is using 100% CPU, 15% - 20% of the Nvidia GPU and 15% - 20% of the Intel GPU. That's neat it can use both, but apparently it's not using both well. (Wait, is one decoding, the other encoding? That is cool.) Is there anything I can do to use either GPU more efficiently?

Re: Improving render performance

PostPosted: Tue Jan 14, 2020 5:06 pm
by Romualdas Budriunas
Which version of Resolve - free or Studio? Free uses mainly CPU for rendering, only Studio uses hardware-based encoding for H.264.

Re: Improving render performance

PostPosted: Tue Jan 14, 2020 5:09 pm
by Pixelslayer
Romualdas Budriunas wrote:Which version of Resolve - free or Studio? Free uses mainly CPU for rendering, only Studio uses hardware-based encoding for H.264.


Free version. I thought the free version could use 1 GPU, but only Studio could 2 or more GPUs.

Re: Improving render performance

PostPosted: Tue Jan 14, 2020 6:30 pm
by xunile
Are you using Text titles or Text+ titles?

Re: Improving render performance

PostPosted: Tue Jan 14, 2020 6:38 pm
by Pixelslayer
xunile wrote:Are you using Text titles or Text+ titles?


Plain old Text titles (not Text+ to be clear.)

Re: Improving render performance

PostPosted: Wed Jan 15, 2020 4:06 am
by Pixelslayer
Well I've done some testing with this and came up with some interesting results. On the laptop above, the project I referenced completed in 27 minutes (about 26 fps.) I also tried on another laptop with an i5-7300hq and GTX 1050 Ti. I expected this laptop to blaze through the render with little trouble, but it took 24 minutes with the exact same project and settings. Note that this 2nd laptop has some power/battery issues, but otherwise seems to function OK.

The real surprise was when I got a 2017 MacBook Air. Keep in mind that this is a dual core i7, not a quad like the other two laptops. And instead of an Nvidia card, it has the Intel HD 6000 GPU. It crunched through the same render in 13 minutes. That's nearly realtime, and roughly twice as fast as the other laptop.

I decided to explore this a little further and booted up Boot Camp on the MacBook Air and installed Resolve 16 in Windows. Instead of 13 minutes, the render took 45 minutes. Finally, I moved the project over to 2012 Mac Pro (3.3GHz 6-core Xeon with an AMD HD 7950.) Once again the render took 24 or so minutes. What voodoo has Apple done with their Intel encoder??

So does this mean for the fastest video exports should I get a MacBook Pro with an Intel GPU? That seems crazy considering the powerful GPUs that Blackmagic recommends for Resolve.

If I do get a MacBook Pro with a dedicated GPU, will Resolve be 'smart' enough to use the Intel GPU when appropriate? Would I be better off just getting an external GPU for my MacBook Air for those effects that need an AMD/Nvidia GPU?

Re: Improving render performance

PostPosted: Wed Jan 15, 2020 9:23 am
by roger.magnusson
Pixelslayer wrote:
Romualdas Budriunas wrote:Which version of Resolve - free or Studio? Free uses mainly CPU for rendering, only Studio uses hardware-based encoding for H.264.


Free version. I thought the free version could use 1 GPU, but only Studio could 2 or more GPUs.

Both statements are true for Windows.

The difference is that on macOS Resolve uses the OS to encode H.264, allowing the hardware encoder to be used even on the free version of Resolve.