eGPU video playback performance is terrible

stevey500

macrumors 6502
Original poster
Sep 8, 2004
395
2
Salt Lake City, Utah
Hardware used: 2018 13" Macbook Pro i7 8559U Mojave 10.14.1 paired up to a Thunderbolt 3 Aorus eGPU enclosure with an AMD Vega 56 8GB GPU

Macbook in Mac OS> eGPU > Displayport > 27" 4k LG monitor
4k video playback seems to tank the performance of the whole system to barely-functional. Playback of 4k30 content on youtube in Chrome puts some stress on the processor and utilizes most of the GPU resources. When playing back 4k60 content, I get occasional stutters, CPU usage is high, and eGPU usage is 100% pinned.

The same behavior exists when playing back 4k60 content in quicktime whether it is h264 250mbps or 50mbps h265 content. I also get the same results utilizing VLC, the h265 50mbps file severely struggled.

As long as I am not playing back high bitrate video content, the system runs beautifully- even playing Dirt Rally in 4k gets me an average ~60FPS and extremely smooth system performance. Running FCPX also runs quite well and exports content rapidly, in comparison to the iGPU of course but it does not tank the system and choke everything.

4k display > Macbook
If I disconnect the eGPU and connect the display straight into my macbook, these files play back just fine. The h265 55mbps file plays back in VLC at about 70% iGPU usage smoothly, h264 250mbps file plays back at ~40% iGPU usage. Youtube 4k60 video content plays back in chrome at about 65% iGPU usage.

Macbook in Windows 10 > eGPU > Displayport > 27" 4k LG monitor
I decided to reboot into Windows 10 with the eGPU connected and do the exact same tests with the same youtube videos and same video files. I found that 4k60 video on the web worked perfectly smoothly in windows without tapping out the eGPU at all. The h264 and h265 high bitrate 4k60 files played beautifully in VLC.

I feel as though there is some software optimization issues with video rendering on Mac OS through an eGPU. Can anyone else here verify this with their eGPU setup?
 
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stevey500

macrumors 6502
Original poster
Sep 8, 2004
395
2
Salt Lake City, Utah
No one?

I was able to test another setup at our office. A 2016 i7 13" macbook pro with Akitio Node Pro Vega 56- same exact result when trying to play back 4k60 content of very high bitrate or via chrome in youtube.

There's definitely something choking video decoding with eGPU in Mac OS. Windows shreds all of these tests with flying colors on the same hardware on both setups. :( Hope apple can fix this. It now makes sense of why some people's eGPU tests with dedicated graphics in their 15" macbook pro models had some strange playback issues in fcpx with the eGPU but no playback issues when not using the egpu.
 

AlexMaximus

macrumors 6502a
Aug 15, 2006
823
231
A400M Base
No one?

I was able to test another setup at our office. A 2016 i7 13" macbook pro with Akitio Node Pro Vega 56- same exact result when trying to play back 4k60 content of very high bitrate or via chrome in youtube.

There's definitely something choking video decoding with eGPU in Mac OS. Windows shreds all of these tests with flying colors on the same hardware on both setups. :( Hope apple can fix this. It now makes sense of why some people's eGPU tests with dedicated graphics in their 15" macbook pro models had some strange playback issues in fcpx with the eGPU but no playback issues when not using the egpu.
I am very interested in this eGPU topic. However, my conclusion was that the support and the drivers in macOS are not "there" yet. I watched many eGPU reviews on YouTube. Most will tell you that Apple needs more time to adapt software and drivers to fully utilize a device like that. For the time being, I would not advise getting one. Maybe in a year the story will look different, but not at the moment. The best page on eGPU is the egpu.io page. Google it, they may have some homebrew solutions like the script for the "eGPU-unsupported" Mac Pro 6.1 from 2013.
 

stevey500

macrumors 6502
Original poster
Sep 8, 2004
395
2
Salt Lake City, Utah
I am very interested in this eGPU topic. However, my conclusion was that the support and the drivers in macOS are not "there" yet. I watched many eGPU reviews on YouTube. Most will tell you that Apple needs more time to adapt software and drivers to fully utilize a device like that. For the time being, I would not advise getting one. Maybe in a year the story will look different, but not at the moment. The best page on eGPU is the egpu.io page. Google it, they may have some homebrew solutions like the script for the "eGPU-unsupported" Mac Pro 6.1 from 2013.
I'm going to have to go ahead and agree with you. I hope the fix this. This is bonkers that apple would be supporting and exclusively selling their own Blackmagic branded eGPU units with such a bug in the software especially at the high price they want. I'm only $600 into my tiny and conveniently portable (if need be) vega 56 egpu vs apple's $1200 asking price.
 

NJPitcher

macrumors regular
Aug 26, 2006
145
1
Something is not right with your hardware. I have an AMD Vega 64 with a Razer Core X (on a 2014 MBP even, so I'm using a script to enable play over TB2) and it is plug and play, and I run games on high at 4k with respectable framerates. What enclosure are you using? You mention that it's portable - do you have an adequate power supply for your card?

Edit: I see you actually don't have an issue gaming, and it's the playback that suffers. I'll try it out on mine when I'm home, sorry for the irrelevant response (so far).
 

stevey500

macrumors 6502
Original poster
Sep 8, 2004
395
2
Salt Lake City, Utah
Edit: I see you actually don't have an issue gaming, and it's the playback that suffers. I'll try it out on mine when I'm home, sorry for the irrelevant response (so far).

Would appreciate that. Open Activity Monitor, command+4 and play back full screen 4k60 content in chrome, does your eGPU max out when played back in full screen? Some 4k60 content at high bitrate stutters and struggles maxing out my eGPU. This doesn't happen in windows.