What power supply and percent is needed for the mat. fees?

Question

MSI

Good afternoon !
I am building a PC for various needs and games as well. Under mat. the board was chosen msi z390 gaming edge. Intel i7 9700K was selected from the processor, that is, the 9th generation Intel processor, under the Z390 chipset. I heard that this mat. the board requires BIOS firmware to work with this processor, is it so? Plus, I see in this motherboard two connectors for power supply connectors (4 pin + 8pin) is it really necessary to power both connectors or is only 8 pin enough? Again, on the Internet, they write about this that 8 pin with a head is enough, and 4 is an excess for overclocking. And another additional question, can anyone have this mother, does it matter which connectors to insert RAM into?