the threat is closed... so sorry for the new one
i changed the following in the BIOS settings, now 5 cards no Problem, no EFI Error
Settings / Advanced / PCI Subsystem Settings
PEG0 - Max Link Speed ----- from Auto to Gen1
PEG1 - Max Link Speed ----- from Auto to Gen1
PCI Latency Timer ----- 32 PCI Bus Cl.
Abobe 4G decoding ----- from disabled to Enabled
for other miner which also starters, mining now with 5 RX 480 default BIOS and default settings with 123 MH/s Ethereum with 550W consumption. Next step is so change the bios for better consumption and higher MH/s. Actually one card makes 24,x MH/s possible are 27-28 MH/s.
i changed the following in the BIOS settings, now 5 cards no Problem, no EFI Error
Settings / Advanced / PCI Subsystem Settings
PEG0 - Max Link Speed ----- from Auto to Gen1
PEG1 - Max Link Speed ----- from Auto to Gen1
PCI Latency Timer ----- 32 PCI Bus Cl.
Abobe 4G decoding ----- from disabled to Enabled
for other miner which also starters, mining now with 5 RX 480 default BIOS and default settings with 123 MH/s Ethereum with 550W consumption. Next step is so change the bios for better consumption and higher MH/s. Actually one card makes 24,x MH/s possible are 27-28 MH/s.