- Nov 3, 2019
Regarding youtube, anything above 1080p uses VP9 codec instead of H.264. Apple does not support hardware decoding of VP9 in MacOS, so when you watch 4K videos on youtube they are decoded in software on your CPU.Hi. I finally unpacked the 5K and hooked it up to the left-most TB port on my Mac Mini. I have an eGPU with a Radeon 580 on the right most port. I have designated the LG 4K monitor I have as my primary, as I understand that it leads to higher likelihood that both displays use the eGPU? Not sure that's correct.
I have also gone through and updated the Get Info preferences on a bunch of key apps to preference the eGPU. But I still felt like I was getting some choppy scrolling.
I then went ahead and watched a 4k 60Hz video on YouTube via Firefox (also with preference eGPU box set).
Notably, in GPU History in System Monitor, the eGPU was clearly working with pretty high blue bars. The video was really nice and smooth on the 4K (which is connected via DisplayPort to the eGPU). But when I moved it over to the LG 5K, lots of frames were dropped. Nonetheless, the GPU History continued to seem like the eGPU was being used.
Is this just a function of having that many more pixels to push (for the exact same content)? I would have thought that a reasonable GPU like the Sapphire Radeon 580 would be more than enough for something like that. Or am I not really getting the eGPU to work?
The screen is beautiful to look at, but concerned this set up is a fail, if I can only use the internal GPU...
Thoughts? Has anyone had experience with set-eGPU?
EDIT: One additional note. I have a Akitio TB3 box with my User drive attached to the TB3 port next to the eGPU. Is that a mistake? What would be optimal if I have:
1. LG 5k Ultrafine
2. Akitio 4 drive TB3 enclosure
3. Razer Core eGPU enclosure
To get the most performance from an eGPU, your monitors should be connected directly to the eGPU, otherwise the video signal has to be routed back into your system then passed to your monitors. I think the performance loss averages ~15% but can be higher. You could try connecting the 5K monitor to your eGPU with an adapter cable like this one, but I have no idea if that actually works. Otherwise you are stuck connecting the 5K directly to your Mac, and you should at least connect your 4K monitor directly to the eGPU, which should work even with an adapter cable(if required).
The four TB3 ports on your Mac mini share two controllers(one for each pair), so you would probably want your eGPU on one pair, and your akitio drive on the other pair. And if you do have to keep your 5K connected directly to your Mac then it's up to you to determine which side should take the performance hit.