EGPU - RTX3090 - Rocky Linux performance testing app

I have a Dell Precison 7760 laptop running Rocky Linux 8.8 that is connected by Thunderbolt to a Razer Core X EGpu box, that contains a Geforce RTX 3090 .
I would like to do GPU speed tests in linux to see deduce how much of the full power of the card is being used. I presume that the Razer and the single thunderbolt cables are bottle necks, but I would like to work how much I am losing. Any ideas are most welcome. Thank you