RESOLVED:
with a dvi-d to dvi-d cable (not dvi-d to hdmi or hdmi-hdmi) can get signal to monitor and see BIOS finally. Definitely tried this on the gfx card i returned so perhaps there was something wrong with that in the end
New intrigue:
From what I gather from wiki, ryzen 5 2600 would be pinnacle ridge, and looking at QVL on gigabyte b450m
https://www.gigabyte.com/Motherboard/B450M-GAMING-rev-10/support#support-doc
and the pinnacle ridge series...
Hi,
Bought the following components:
AMD Ryzen 5 2600
Gigabyte GA-B450M Gaming Motherboard
Sapphire Pulse Radeon RX 570, 8GB
G.Skill Ripjaws V F4-3000C15D-16GVRB 16GB (2x8GB) 3000MHz DDR4
Corsair CX650M 650W Bronze Power Supply
-Fans would spin etc but no video output from gfx card on either...