Hi Guys,
I am new here and I was also having the same issue , till 2 GPUs Z270P was working fine but once I add my 3rd GPU windows was crashing. So I upgrade bios 1st to the latest version of now which is PRIME-Z270-P-ASUS-0610.CAP , For me also Internet download was not working so simply I install from usb stick.
1st : Upgrade BIOS to 610 version
2nd : Go Advanced ----> System Agent (SA) Configuration ----> Enable "Above 4 G Decoding"
3rd : DMI/OPI CONFIGURATION ---> DMI MAX LINK SPEED change to GEN1
4th : PEG PORT CONFIGURATION ---> PCIEX16_1 LINK SPEED change to GEN1
Thats all I did not change PCH CONFIGUTATION configuration like other bro did and for me now mining is stable and running without any windows crash etc. from last 20 hours.
Share is care. So keep sharing and keep Caring
Kudos
Rebel
This config worked for me. I couldn't make it work with more than 4 GPUs
Special notes: I had the latest BIOS installed. I think it's 0810
I had connected my monitor to my onboard GPU and did not work.
I disconnected the monitor and started windows 10 with no monitor. I usually connect and manage my miner with teamviewer or google remote desktop.
it worker with 5 GPUS.
Thanks for your great help.