Razer core x+5700 XT+2013 mac pro, running no problem, but I can't see the gpu b...
 
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Razer core x+5700 XT+2013 mac pro, running no problem, but I can't see the gpu bring me any better performance than internal firepro D300 in Davinci. what am I worng?  

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BlakeYang
(@blakeyang)
New Member
Joined: 5 months ago
 

2013 mac pro 4 core 3.7Ghz 

64Gb ram

1T ssd

Apple TB3 to TB2 adapter

Apple TB2 cable

Razer core X TB3 egpu enclosure

Amd 5700 XT 8G

purge wrangler

set davinci prefer external gpu. (davinci version 16.2) (mac os big sur)

the egpu runs no problem, can see it in "about this mac" as a primary video card and in system report (graphic car and thunderbolt).

Geekbench 5 testing result is 68325.

Im not a gamer, I just use it in davinci resolver for editing and color grade video. 

use internal graphic card (firepro d300) playback the footage smooth, but if I choose egpu to playback same footage, only can get 18fps. footage format is bmpcc 4k raw. 

in davinci preferences I set manuel metal.

so confused. anyone know the reason or it's running normal. thx!

This topic was modified 5 months ago

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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ScreamingPict
(@screamingpict)
Eminent Member
Joined: 2 years ago
 

I'm no expert but here's some things to check;

 

1- Open Activity monitor whilst running DaVinci and verify that the 5700 XT is taking the load. Is it maxed-out? (presumably not) Is it being used at all or are you being the built-in GPU being used?

If it is being used and is not maxed-out then the issue could be bandwidth:

2- TB2 is limited to 20Gbps. With bi-directional traffic you'd be dividing that in half again to 10Gbps (I believe). In reality you'd get a lot less than that in total so maybe 5Gbps each-way with all the overheads and with the real transfer rates.

bmpcc raw 4K bandwidth depends on the compression ratio, but at 3:1 compression it's transferring 1Gbps. If that data is sent uncompressed to the GPU (I have no evidence that it is or is not- I'm not a pro) then it'd be sending 3Gbps each way constantly, which would seem like it'd still be low enough to achieve the full frame-rate, but it's definitely getting close to what would be achievable on a TB2-TB3 setup.

2018 Core i9 15" Macbook pro, Razer CoreX Chroma, AMD RX580


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BlakeYang
(@blakeyang)
New Member
Joined: 5 months ago
 

@screamingpict, Thx a lot.

1 - Activity monitor shows that the egpu usage rate is almost 100%. internal graphic cards usage around 90% both. cpu usage close up 90%.

2 - agree your point, should be the TB2 bandwidth not enough. the raw footage is 5:1 compression.

 

I did a test in windows 10 with 5700 xt, plug it into pci-e slot. same footage, same workflow, running great. but when I opened task monitor, I guess I find out the answer.

my windows hardware is I5-4690k 3.5GHz, 16G ram, plus 5700 xt.

The task monitor shows that cpu usage only 45%, gpu usage 7%, very interesting ah, but the graphic ram usage is 100%. when I add 1 more node with Denoise in davinci,  fps drops from 25 to 16.

 I don't think that windows's OpenCL is better than mac's metal. so the key point is Tb2 bandwidth I think. 

Then I did a render test back to mac os with egpu, in same video, render with egpu spend 5mins and 3 secs, 22 mins and 46 secs without egpu.

from this result I can only say the egpu can not raise the editing and color grading experience on Tb2. maybe feel better on Tb3.... 

 

 

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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ScreamingPict
(@screamingpict)
Eminent Member
Joined: 2 years ago
 

Interesting- surprising that Activity monitor would show the 5700 XT as 100% if it was bandwidth-limited. But yes, overall your testing would make me think you'd do better with a TB3 connected Mac.

2018 Core i9 15" Macbook pro, Razer CoreX Chroma, AMD RX580


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BlakeYang
(@blakeyang)
New Member
Joined: 5 months ago
 

@screamingpict, I got CL!ng today. egpu's bandwidth is so terrible. in TB2, only 18Gbit/s, 10Gbit receive and 8Gbit send data back..... it's too narrow, even use it in TB3, only can get 40Gbit/s bandwidth for both way. but I saw the internal gpu bandwidth, sent and receive both way working over 180Gbit/s.

Im gonna sell my egpu. it's useless for me.

 

thanks again scremingpict. good night. 

 

This post was modified 5 months ago

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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joevt
(@joevt)
Noble Member
Joined: 4 years ago
 

Thunderbolt has separate lines for send and receive so send and receive should not affect each other much.

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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