Multiple gpu problem with Asrock B 450 K4

Greetings. My system boots find when only gpu installed. Once I add the 2nd gpu (two identical rtx 2080 super) system wont post and kick me straight to bios settings, including no video signal from either gpu and 2nd gpu no matter which is connected would stop spinning all it's fans and kicks me to bios again. My psu is 1450w Gold. It's endless loop. I cleared SMOS multiple times, tested each gpu with difference power cables, changed PCI-e slots for each gpu. Again, 1 works, once 2nd connected same problem persist.Nothing helped.
Is this mobo even supports multiple Nvidia gpus?
Also in BIOS there is no such option as Chipset Advanced settings to enable IGPU multi monitor and CPU does come with radeon graphics
I want to use it for mining, I tested each card with each riser, as long as 1 card plugged in then its fine. Thx for any help , appreciate your time and forgive my grammar, still learning it as my ESL
1Chieftec Power smart PSU 1450w GOLD
2 CPU AMD Athlon 200GE AM4
3 DDR4 Gskill 2666mhz 8GB
4 Asrock b450 Gaming K4

To make this discussion as helpful as it can be I want to inform everyone that I checked all cables very carefully and plugged all necessary power cables to correct connectors, 2 8pin to gpus etc

datonyb wrote: clearly shown in the product details is crossfire only guess that two more gpus that can actually be used by people to game rather than push up prices and remove stock levels for mining

No, GPUs do not need to be in xfire in order to work :)
I have few ideas what might be wrong, but I did not respond on purpose due to my attitude towards miners.