Adding Second GPU and System Wont Boot

I currently have an RTX 3090 installed in my main system. It has been running fine and hashing away for a while. Recently, I purchased an RTX 3070ti to install in that system as well. I cannot get my system to boot with both installed. Both GPUs work as they should, but when both are installed the system, it doesn’t turn on. What could be causing this and how do I fix it? My PSU is an RM850 which is plenty of power for both. I think it is something in the BIOS that may be causing this?