Blackmagic EGPU and ImacPro

Howdy,
I was thinking of buying the BLackmagic eGPU to use with my 2018 Apple 27-inch iMac Pro Retina 5K, 3.2GHz 8-core Xeon W (Current Model) with Thunderbolt 3, 64GB DDR4, 1.0TB SSD, Vega 56, running on macOS 10.13.x High Sierra.

Will I gain anything in performance from using the eGPU? Does the eGPU have any issues with High Sierra?

I'm using this mac to edit 4K and 3D if anyone is curious.

Yes, you will get extra performance, but it depends a lot on the function you use. NR, for example, will be nearly twice as fast, while some other functions hardly profit at all. If that Vega has more VRAM than 8 GB, your system will behave as if you have 8 only, it’s always depending on the smaller one, i.e. they don’t add up.

Ahh. Yes I was wondering that. And also when you consider that the external eGPU relies on going thru the bottleneck of the mac's thunderbolt connection is it really gaining anything or worth the expense?

Thunderbolt 3 isn't much of a bottleneck, but I don't think you'll gain enough performance for it to be worth the cost in my opinion.

Seconded. It makes a lot of sense with weaker machines, but not so much with an iMacPro.

I would not spend the money on the BMD eGPU, it is far too expensive for what you get. The BMD eGPU Pro costs about $1200 but you can buy the Vega 56 for $450, and a chassis for $300.

I think it is worth it to have an eGPU on an iMac Pro. Resolve often uses both my Vega 64 and Radeon VII fully. Not everything is noticeably faster - especially Fusion - but Noise Reduction which is very slow, is at least only half as slow.

Just check https://barefeats.com/

Misha: can you be more specific? barefeats is an interesting site, but a dumping ground of all sorts of random GPU-related information. What exactly were you suggesting people look there for in relation to the question about an eGPU and the iMacPro? Was there a particular article that you felt addresses the question? I only saw one that mentioned the BMD eGPU, and it had very little information.

Every article that mentiones GPU or Davinci Resolve.
Within 5 minutes you have a ton of information.
When you can't find it on this site, stick to your iPhone or iPad.

Another great source is egpu.io