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TOPIC: Anyone else having sluggish egpu performance in FCPX 10.4.5?

Anyone else having sluggish egpu performance in FCPX 10.4.5? 11 Mar 2019 07:21 #99240

  • viprit
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Had posted about egpu woes in different subreddits but I recently upgraded from a Mac Pro 5,1, because of its aging infrastructure to a 2017 iMac 5k i5 3.8ghz 8GB RAM with a Radeon Pro 580 8GB in it because I got a deal on it.

I figured I’d upgrade with an egpu through TB3 to add even more power since that was a thing now. Got the Sonnet eGFX egpu 550w box (was $50 off) before I bought my Sapphire Nitro+ Vega 64. After seeming like something was a little weird, I upgrade the PSU in the box to 750w. Now things seem to be running more correctly.

I figured I’d get more performance on Unigine Valley than average 35-40fps on 2k ultra settings. For 1080p it hovers around 60fps avg.

even though FCPX seems to be “using” the Vega in the activity monitor, everything seems really sluggish no matter what I do.

I heard the egpu was more supported in FCPX 10.3 over 10.4.

Anyone having similar issues?

Should I just get rid of this setup and go back to a 5,1 Mac Pro and throw the Vega 64 in there?
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Anyone else having sluggish egpu performance in FCPX 10.4.5? 13 Mar 2019 13:21 #99276

  • joema
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viprit wrote:
Had posted about egpu woes in different subreddits but I recently upgraded from a Mac Pro 5,1, because of its aging infrastructure to a 2017 iMac 5k i5 3.8ghz 8GB RAM with a Radeon Pro 580 8GB...I figured I’d upgrade with an egpu through TB3 to add even more power since that was a thing now. Got the Sonnet eGFX egpu 550w box (was $50 off) before I bought my Sapphire Nitro+ Vega 64....even though FCPX seems to be “using” the Vega in the activity monitor, everything seems really sluggish no matter what I do....Should I just get rid of this setup and go back to a 5,1 Mac Pro and throw the Vega 64 in there?

Your 2017 iMac -- without the eGPU -- will be much faster on H264 material than the Mac Pro 5,1 because it has Quick Sync. So I'd stay with the iMac no matter what.

Re "everything seems really sluggish no matter what I do", I assume you mean FCPX since this is a FCPX forum. What codec and what editing operations are slow?

For editing with FCPX, many tasks are CPU-bound, not GPU-bound. A faster GPU won't magically make everything go faster. Certain very compute-intensive effects like Neat Video are only partially accelerated by a GPU.

In general, import, export and transcoding are not accelerated by a GPU or eGPU. Certain GPU-accelerated effects can be.

A very GPU-bound FCPX benchmark is BruceX. You can try this with and without the eGPU to see how much improvement it makes. On my 2017 i7 iMac 27 with Radeon Pro 580 and running Mojave 10.14.3 and FCPX 10.4.5, BruceX takes an average of 18 sec. On my 10-core Vega64 iMac Pro, it takes about 12.5 sec: www.fcp.co/forum/hardware/18250-brucex-t...-cut-pro-x-benchmark

You need to use the Thunderbolt 3 cable which came with the eGPU, an Apple Thunderbolt 3 cable or a certified, known good Thunderbolt 3 cable. Any other cable could cause slowdowns or unpredictable behavior. The cable should run directly to the eGPU, not daisy chained through any other device, nor from a hub.

With a compatible eGPU, FCPX can be faster -- at certain things. You need to use the "prefer eGPU" option: support.apple.com/en-mz/HT209134

Here's a video discussing aspects of how an eGPU interacts with FCPX:

BlackMagic eGPU review and test:
www.google.com/url?sa=t&rct=j&q=&esrc=s&...U6EUgt0cXmvJg4xHX-_Q
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