Hi. Like you, I have just purchased a WX9100 GPU and installed it into a Razer Core X eGPU enclosure and, like you you, I am getting the same problem. When Plugged into my 2017 iMac Pro and powered up it emits a piercing alarm noise. Needless to say I immediately powered down and unplugged the eGPU. The spec of my iMac is pretty much identical to yours.
Did you find a solution to this problem?
Sorry to hear that. So far, yes I did (fingers crossed since I really tested it last week) and tonight will do again under streaming conditions.
I checked all software installed, I believe there was a bad interaction with some Kext files of either NTFS for Mac or Box (cloud storage). I updated NTFS to latest version, I now close Box during streaming, unplug Time Machine hard drive...
As I said, never understood who was (I hope it stays in past tense) the culptrit.
Thank you for your quick reply. I will try disconnecting my Time Machine.
I saw the picture you posted showing the power supply plugs. Am I right in saying that you placed one 6 pin plug in the lower 6 pin socket and the remaining 6 pin at the top of the upper 8pin socket with the small 2 pin plug placed in the remaining two, free holes? Please see my picture.
Is this correct or is it not necessary to insert the 2 pin?
Thank you for your help.
The AMD support is awesome, they will let you know better than me about the pins. I closed the box and I do not want to open it again. They will answer you for sure.
I forgot something crazy, I also changed the colour profile of all my external monitors. I always felt external monitors were involved.
Did as you suggested; shut down iMac, removed all peripherals, plugged in Razer Core X with WX1900 and switched on, booted up iMac Pro and all worked well! Gradually reintroduced the peripherals without any problems (so far).
A big, big thank you for all your help.