Try
Has anyone tried using SimpleMining with the TB250-BTC board? I can't seem to get more than 3 cards working without getting PCIE bus errors and I've tried most troubleshooting changes in the bios.
I just want someone who is living proof that someone is using this board with simplemining OS, who is using this motherboard and can you list the bios settings any other settings you've changed in order to get 6 cards running ?

i've found that adding a linux command 'pci=nomsi' gets rid of the error messages but i'm unsure of how healthy / stable that is.
Try unplugging molexes from the board if you have powered raisers.
Crazy, I know. But when I plug in molex only 3 cards work.