Upgraded to Sierra 10.12.6 successfully, (almost) everything is working - Computer wakes from sleep, but monitors do not

Hey All -

Thanks to the help of this forum, I've got my hackintosh updated to Sierra with just about everything working. The only problem I seem to be having now is that when the computer sleeps, the monitors will not turn back on when it wakes. The computer fires back up (fans/hard drives start spinning/mouse turns back on), but the monitors remain black/no signal.

Any thoughts or ideas on correcting this? I've tried tweaking the BIOS with no luck.

Computer specs if it helps:

• Intel Core i7-2600K Processor 3.4GHz 8 MB Cache Socket LGA1155 (Sandy Bridge)

• Gigabyte LGA 1155 Intel Z68 Motherboard GA-Z68MX-UD2H-B3

• XFX ATI Radeon HD6870 1 GB - HD687AZNFC

• Corsair Vengeance Blu 16 GB PC3-12800 160mHz DDR3