I should probably rephrase. I have all 6 GPUs on risers, the only time it does not post is when I have 2 of the x16 slots with the risers in them. I will double check and make sure they are all the same gen type. I had it on auto first but when I did, it wouldn't even boot past one card. I'm to the point I may just reset the MB bios via cmos and start fresh.