macOS and AMD Radeon RX 6900 XT are working flawlessly except GPU is a much more HOT than expected!

It may be acceptable to the manufacturer, but it is not working correctly if it is getting that hot in comparatively normal use.

I suspect the fan on the card is not spinning. At all. Check to make certain the fan on the card is spinning.

In general, Mac Software does NOT control the fans on the card, only the fans on the cabinet.

Over 100 Celcius is NOT "OK"

Is the fan on the card running? (the side door is not interlocked and can be removed with the unit running.

Europeans are warned not to stick their fingers in the fan blades [the EU forced these units off the market because there was no interlock on the door])

12 Volt power is used to power the card, and also to run the fans. If your enclosure does not provide enough power, or you have "cheated" on the power connections, this could indicate a Power problem.

Hey @sowson,

I just bought RX 6900 along with sonnet 750ex. But it is not showing in my 2020 iMac.

You said it is now working as eGPU.

Do I need to do anything to make it work ?

Am I missing something ?

Appreciate your time. Really need some help or information how to make it work.

Thanks Grant, but mine is iMac 2020 and it should work right ?

you can find my full stories here

1) https://discussions.apple.com/thread/252829429?login=true&page=1

2) https://egpu.io/forums/mac-setup/radeon-rx-6800-xt-for-mac/paged/23/

Well, I am the one who tested the eGPU on thunderbolt 2 to thunderbolt 3 converter it is working perfectly even for NAVI 21 XTXH.

I can confirm that 110% it is working.

Navi 21 RX 6900XT XTXH card, which was Sapphire RX 6900XT Toxic Extreme Water-cooled, I tested was working perfectly on iMac 2013 i7 via Thunderbolt 2 port with thunderbolt 3 converter on Bootcamp (only). I tired with both Blue and Red driver from Bootcampdriver.com and both are working.

Support for the 6900 XT apparently first appears in MacOS 11.4. that may be problem for the Mac Pro 5,1.

Requires ThunderBolt-3 ports, which your older iMac does not appear to have.

Sonnet comes with 750W and Razer comes with 700W. I have bought 850W Cosair PSU. However, the GPU maximum required W is just <420W. I have done many inquiry about the power and all said 700W is enough. The Razer Core X stated the the eGPU box comes with 700W can handle all graphic card maximum power of 500W.

The graphic card have 2x8pin and 1x6pin. I bought Y Splitter cable for that but I have also use Coair PSU with Cosair cable. Same.

A professional one told me the card is using NAVI 21 XTXH and apple is currently supporting NAVI 21 XTX even they all are under RX 6900XT categories. Strange.

One strange thing is I have tested on Bootcamp on 2 iMacs. One is mine 2020 iMac with 5700XT and another is my friend iMac 2013 with Nvidia 780M.

The card works flawlessly on his 2013, i7 with Nvidia 780M Bootcamp but it is not working even on Bootcamp on my 2020 iMac.

we both use same driver from Bootcamp driver but nothing can work the card to work with 2020 iMac.