eGPU for iMac2019

[Daniel Roy]

Hi,

I work on v large psb files - think 25k pixels by 30k, w/ layers and masks.

I have a 2019 iMac that I want to keep because of its excellent 5k screen.

Here is my setup

• 3GHz 6-Core Intel Core i5
• Radeon Pro 570X 4 GB
• 64GB 2667MHz DDR4
  
• 4Tb SSD
• 2Tb scratch disk

To further improve the performance with v large pictures, I bought

• an external GPU, a SAPPHIRE Pulse AMD Radeon RX 6800 16 GB GDDR6 memory (the Radeon Series 7 seems not to be compatible)
• enclosed in a Razer casing 

The card is recognized by the Mac, all good here. However I have the feeling it's not used at all by Photoshop.

• In Photoshop/Settings/Performance it continues displaying the internal AMD Radeon 570 card w/ 4 Gb, not the eGPU 5700 with 16. 
• When looking at Activity Monitor and using Camera Raw, Perspective Tilt, Liquify, I dont see any usage of the 5700. 

To be absolutely honest, I brefly saw some activity on the eGPU, see snapshot, but the bulk of the activity seems to always be anyway on the built-in card. 

Thoughts? Was I naive thinking Photopshop would be using the eGPU?

I use Photoshop 2025 and Sonoma 14.5. 

Thank you all
Dan

[Daniel Roy]

Restarting this thread to check if anyone did found a robust solution ?

I havent yet explored the 'ghost/dummy display port plugs in the eGPU' solution and not hyper-willing to either, you would hope this could have had a systemic solution...

Posted something fairly similar here

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Hi,

I work on v large psb files - think 25k pixels by 30k, w/ layers and masks.

I have a 2019 iMac that I want to keep because of its excellent 5k screen.

Here is my setup

• 3GHz 6-Core Intel Core i5
• Radeon Pro 570X 4 GB
• 64GB 2667MHz DDR4
  
• 4Tb SSD
• 2Tb scratch disk

To further improve the performance with v large pictures, I bought

• an external GPU, a SAPPHIRE Pulse AMD Radeon RX 6800 16 GB GDDR6 memory (the Radeon Series 7 seems not to be compatible)
• enclosed in a Razer casing 

The card is recognized by the Mac, all good here. However I have the feeling it's not used at all by Photoshop.

• In Photoshop/Settings/Performance it continues displaying the internal AMD Radeon 570 card w/ 4 Gb, not the eGPU 5700 with 16. 
• When looking at Activity Monitor and using Camera Raw, Perspective Tilt, Liquify, I dont see any usage of the 5700. 

To be absolutely honest, I brefly saw some activity on the eGPU, see snapshot, but the bulk of the activity seems to always be anyway on the built-in card. 

Thoughts? Was I naive thinking Photopshop would be using the eGPU?

I use Photoshop 2025 and Sonoma 14.5. 

Thank you all
Dan

[Daniel Roy]

Hi - no one has a view? 

[Claire H.]

Hi @danielr2300940, Thank you for reaching out. Could you tell me more about where you’re seeing this issue?  If possible, please also share a screenshot of Lightroom and a copy of your system info. You can find it by going to Help > System Info, then copying and pasting it into a text file to attach here. This will help us look into it further.

Also, just a quick reminder, here are the minimum system requirements needed for Photoshop software: https://adobe.ly/43UezwO

Once you send that over, we can continue troubleshooting this issue. Thanks! ^CH