Hi, I'm right before investing in external GPU on Mac since Metal render engines are showing up (Octane X & Redshift). My two biggest concerns (which I take in mind for future possibilities of expansion) are:
- Should I use 'proper' way of setting up eGPU via TB or should I make a modification inside my Mac to use faster M.2 slot?
- In terms of scalability, what's the best:
- multiple eGPU cases plugged into TB ports?
- multiple eGPUs + M.2 eGPU?
- multiple GPUs connected to PCIe splitter to M.2 (mining rigs?)
I take also into account hardware limitations (bandwidth, CPU) since my late 2014 iMac has only two TB2 ports. But I'm really interested after seeing @itsage builds with M.2 eGPUs which are kind of last resort for non TB3 users that want maxed out performance. As I said before I'll mainly use external GPUs for 3D rendering so compute/time factor is hugely important. Why not building a PC workstation? Simply because I want to utilize as much as I can from current setup + Metal apps are just arriving on Apple systems. : - )
If anybody has experience with multiple eGPUs on Mac, please share your thoughts.
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Some posts that are around this topic, very useful and informative:
Itsage M.2 build:
https://egpu.io/forums/builds/2015-15-macbook-pro-4th4cq-rx-580-32gbps-adt-link-rs43g-macos-10-15-1-win10-1903-itsage/
PCIe splitter used in Mac Pro 5.1 connecting 4 GPUs:
https://forums.macrumors.com/threads/amfeltec-pci-express-splitter.2027827/
https://imgur.com/a/suUFy
M.2 vs TB eGPU benchmarks:
https://egpu.io/forums/expresscard-mpcie-m-2-adapters/build-m2-vs-thunderbolt/#post-80524
To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.
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Pls see the build in my sig for the most comprehensive analysis on here of M.2 versus TB3 performance.
eGPU Setup 1.35 • eGPU Port Bandwidth Reference Table
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M.2 (ADT-Link R43SG) + Win10 1803 // compares M.2 vs TB3 performance inc unoptimized H-CPU BIOS [build link]
From my experience with eGPU rendering, this limited bandwidth is not as crucial for raytracing rendering as it would be for realtime applications and I'm not sure you would notice a difference in performance. The rendering process happening on the GPU can take place largely independently from the CPU and it only needs to update the image buffer with a certain (non-realtime) interval. The speed at which this image buffer update happens shouldn't matter much either, as a well-written rendering engine normally doesn't pause its raytracing for this process.
MacBook Pro 15" 2015 (Radeon R9 M370X 2 GB)
Atikio Thunder 2
Gigabyte Radeon RX 5500XT 8GB
Mac OS 10.15.6
@ahr0n, The iMac PCIe drive socket is hard to reach and requires an adapter to fit an M.2 eGPU adapter. I'd recommend going with Thunderbolt eGPU solution for your needs.
• external graphics card builds
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2021 15" ASUS TUF Dash F15 [11th,4C,H] + RX 6900 XT @ 32Gbps-M.2 (ADT-Link R43SG) + Win10 2004 // my 1st RX 6900 XT build [build link]
@nando4 @oscar-j @itsage - thank you for your replies. I agree with you, considering that this setup will be utilized only for 3D rendering, the bottlenecks are not so much important here + the 'proper' way of utilizing TB eGPU seems to be okay : - )
One more question about choosing the right GPU - Does utilizing newest card such as Big Navi or Navi for TB2 Mac (late 2014 iMac, i5 4690) affect lower render speed/time? Will I get lower Benchmark results from OctaneBench, Luxmark or any other OpenCL/Metal Benchmark app if I'd connect those newest card to TB2 instead of TB3 Macs?
To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.
.