Question GPU fans turn on, but motherboard doesn't detect

[Versalin]

Hi all,

decided to replace my old GTX 1070 with an RTX 3070.

1. Downloaded latest driver (460.89) from Nvidia
2. Update bios
3. Seated the RTX 3070 with all power pins connected (using a 850w PSU)
4. GPU fan spins but no display
5. Connected to integrated display - went into bios, and it doesn't detect anything in the PCIE slot
6. When I switch back to my old GTX 1070, everything worked normally

Could this be a defect with the GPU? Was wondering why the fans were able to run still.

 

[Versalin]

For additional info my specs are:

CPU: i7-6700k
MOBO: MSI Z170A Tomahawk
Old GPU: MSI GTX 1070
New GPU: MSI RTX 3070 Ventus 2x OC
PSU: Corsair RM850 Modular