Nvidia eGPU MBP TB3 port underperformance: 16xxMiB/s instead of 22xxMiB/s under ...
 
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Nvidia eGPU MBP TB3 port underperformance: 16xxMiB/s instead of 22xxMiB/s under macOS or Windows+apple_set_os.efi  

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nando4
(@nando4)
Noble Member Admin
Joined: 4 years ago
 

@mac_editor, @lexine reported the issue on Oct-6, which was then confirmed by several other users. 

I had noticed lowered macOS H2D values but it was @lexine that identified a Windows boot via apple_set_os.efi (fake macOS boot) caused the same underperformance. Hence a macOS boot is altering some TB3 parameters that a native Windows boot isn't doing.

eGPU Setup 1.35    •    eGPU Port Bandwidth Reference Table

 
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M2 (ADT-Link R43SG) + Win10 1803 [build link]  


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Hector66
(@hector66)
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Joined: 4 years ago
 

This may not be the same as a graphics-oriented benchmark, but I'm getting close theoretical maximum throughput from a 32Gb Fibre Channel HBA in a Akitio Node connected by TB3 to a 2017 MBP 15 inch.

Screen Shot 2017 10 06 at 3.46.54 PM

MBP 15" - Mid 2017
Akitio Node
MSI GeForce GTX1060 6GB


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goalque
(@goalque)
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Joined: 4 years ago

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nando4
(@nando4)
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@goalque, interesting findings there for sure. Given that the CUDA-Z bandwidth issue occurs under macOS or Windows+apple_set_os.efi, this is then not a Nvidia driver issue. Certainly not since a Windows boot without apple_set_os.efi gives full H2D performance.

It looks like Apple are downgrading the TB3 link performance when doing a macOS boot if they detect a NVidia eGPU attached but not when an AMD eGPU is attached.  Why and will Apple fix this?

Affected users can simply do chargebacks on their  Macbook purchase based on their TB3 ports underperforming when Nvidia eGPUs as outlined in the opening post. Pushback that may see Apple sort out their Nvidia issues.

eGPU Setup 1.35    •    eGPU Port Bandwidth Reference Table

 
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M2 (ADT-Link R43SG) + Win10 1803 [build link]  


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goalque
(@goalque)
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Joined: 4 years ago
 

@nando4: very possible that this has something to do with Apple's macOS 10.13 Thunderbolt drivers when there is an Nvidia eGPU attached. If normal clpeak readings on Linux, then definitely.

I trust clpeak because its source code is platform independent and I got a bit better bandwidth with a shorter 0.5m cable, compared to 1m cable. Those linked results are conducted with the Belkin 40Gbps 0.5m cable.

automate-eGPU EFIapple_set_os.efi

Mid 2015 15-inch MacBook Pro eGPU Master Thread

 
2018 13" MacBook Pro [8th,4C,U] + Radeon VII @ 32Gbps-TB3 (ASUS XG Station Pro) + Win10 1809 [build link]  


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nando4
(@nando4)
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@goalque, given macOS or Win+apple_set_os.efi (fake macOS) boot see equally diminished CUDA-Z NVidia TB3 eGPU performance, wouldn't this point to Apple firmware. the constant in both boots, being responsible for downgrading the TB3 link? Put in another way, the macOS Thunderbolt drivers are not affecting Windows Thunderbolt performance.

eGPU Setup 1.35    •    eGPU Port Bandwidth Reference Table

 
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M2 (ADT-Link R43SG) + Win10 1803 [build link]  


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goalque
(@goalque)
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I can't confirm H2D degradation with apple_set_os.efi yet:

I can retest with the latest MBP firmware.

automate-eGPU EFIapple_set_os.efi

Mid 2015 15-inch MacBook Pro eGPU Master Thread

 
2018 13" MacBook Pro [8th,4C,U] + Radeon VII @ 32Gbps-TB3 (ASUS XG Station Pro) + Win10 1809 [build link]  


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lexine
(@lexine)
Trusted Member
Joined: 3 years ago
 
Posted by: nando4

Affected users can simply do chargebacks on their  Macbook purchase based on their TB3 ports underperforming when Nvidia eGPUs as outlined in the opening post. Pushback that may see Apple sort out their Nvidia issues.

hey, can you please share more details how to request the chargeback ? I will give it try, but here we don't have any apple shops just a premier resellers, and I am sure no-one there would understand the issue.... 

2017 13" MacBook Pro [7th,2C,U] + GTX 1070 @ 32Gbps-TB3 (AORUS Gaming Box) + macOS 10.13 & Win10 [build link]  

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goalque
(@goalque)
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Joined: 4 years ago
 

"Anyone know how CUDA-Z does these measurements?"

@yifanlu: This article explains it well:

https://devblogs.nvidia.com/parallelforall/how-optimize-data-transfers-cuda-cc/

I would like to implement something similar with Metal but timestamp information is not available in macOS SDK:

https://developer.apple.com/documentation/metal/mtlcommandbuffer/1640027-kernelendtime

automate-eGPU EFIapple_set_os.efi

Mid 2015 15-inch MacBook Pro eGPU Master Thread

 
2018 13" MacBook Pro [8th,4C,U] + Radeon VII @ 32Gbps-TB3 (ASUS XG Station Pro) + Win10 1809 [build link]  


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nando4
(@nando4)
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Joined: 4 years ago
 

@goalque, lexine observed on a 13" MBP the 22xx->16xxMiB/s performance degradation when using apple_set_os.efi.  Can you confirm this only occurs on a 13" and not 15" MBP? Do AMD cards also see a performance degradation on the same platform where Nvidia cards are affected?

eGPU Setup 1.35    •    eGPU Port Bandwidth Reference Table

 
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M2 (ADT-Link R43SG) + Win10 1803 [build link]  


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