MSI B250 Gaming Pro Carbon Mobo

[briapt43]

So I built my first mining rig last night with this motherboard, have a 1200 watt power supply, 8gb ddr4 ram, pentium duo core 3.3 ghz cpu
Gpus
2 - msi radeon rx 580 8gb
1 - power cooler red devil radeon rx 580 8gb
1 - sapphire pulse radeon rx 580 8gb

Problem I am having is it will only show 3 of the gpus no matter where I put them, have already trouble shooted the pcie risers they all work. I have even only had 3 installed and moved the 3rd from one pciex1 slot to the other and it still shows up so I know both pciex1 slots work.

Im just wondering if this motherboard can only support 3 gpus max no matter what, I am very new to rig building and mining so if this is true then will take it as a lesson learned lol and look to replace the motherboard eventually but would prefer not to have to do that so early.

Any help is appreciated.

[melt]

Hello, sorry for the late reply, but this is how you set up the motherboard: https://forum.getpimp.org/topic/5076/asus-b250-mining-expert-bios-settings-pimp-os-v2-6