Ok... so my Asus 5090 TUF OC arrived yesterday - but I was away with work. I got home tonight, and one of the first things I did was remove my old 1070ti (yes - it's a long overdue upgrade) and fitted the 5090.
A couple of months ago, I fitted a brand new Corsair RM1000x PSU in preparation for this... so when installing the 5090, I used the specific (unused) 12V-2x6 cable that was supplied with the PSU. No sharp bends in the cable, and all routed neatly.
When I put the power cable into the back of the PC, a little red light came on next to the power socket on the GPU. When I actually powered the PC on, the TUF logo lit up and went through it's cycle... but none of the fans on the GPU came on. No output to my monitor either.
I plugged the HDMI cable into my onboard GPU and loaded up Windows. Device manager shows no nVidia GPU.
I've double checked all connectors, and they're all seated properly. What am I missing?
My Motherboard is a MSI MPG Z490 Gaming Plus - and I updated it to the most recent firmware a couple of months ago.