HerrJordan - did you find a solution to this? I am encountering the same issue with same motherboard and samsung 840 pro. drive doesn't appear in bios when connected to sata 3 ports. sata 3 ports have been verfied, bios is current. no joy.
Sorry for reviving an old thread, but I had the exact same problem with a Samsung 840 SSD boot drive not being detected in BIOS when plugged into the P8Z77-LK's SATA 3 port. Worked fine when plugged into the blue SATA 2 port, but wasn't happy about the SATA 3 ports not working. As a last resort I re-attched the SSD to the SATA 3 port, then went into the BIOS and pressed F5 (Load Optimized Defaults). Saved. rebooted and voila, the computer booted from the SSD normally. So try loading optimized defaults and see if that fixes the issue.