This is not a RAM, motherboard devices, Windows, sexual orientiation or dog breed preference issue.
The problem is Catalyst drivers since 12.6 or 12.8 for Windows limited the number of GPUs to 4. Anything after that will show up with an exclamation mark.
The workaround to this is to remove any and all catalyst drivers (thoroughly). Perhaps use TechPowerUp's cleanup utility. Then disable verified driver installation, reboot and use modified drivers. Final step is to manually install OpenCL.
This has worked on the three rigs I have built, every single time. More details here, closer to the bottom of the page:
https://litecointalk.org/index.php?topic=11761.0Cheers!