GTX 970 Won't Initialize Monitors Until Desktop

[demiankz]

This is a previously fully functional system that's survived three OS upgrades and a handful of other hardware upgrades. All I've done this time is swap in a new GTX 970 for an old GTX 680 that burned out.

GA-X79S-UP5 mobo
EVGA GTX 970 FTW+ ACX 2.0+
Latest Nvidia drivers as of a month ago
BIOS F4u
El Cap 10.11.4

Monitor remains black until about five seconds before the desktop appears, then they recognize a signal from the card, and voila, the desktop appears. So, I'm effectively locked out of the BIOS, Clover, or viewing a verbose boot.

This is a dual boot system. System won't boot with only the Windows drive plugged in. Haven't tried CMOS reset yet for fear of losing access to my OSX installation (reset default boot drive, etc.)

Any suggestions? Thanks.

 

[KONKY1]

It would be okay to do a CMOS reset but make sure you setup your BIOS correctly, including load order for your drives.

Just make sure you take precautions on doing so, backup and the like.

 

[demiankz]

"Just make sure you take precautions on doing so, backup and the like."

To clarify, if this CMOS reset doesn't work, I feel like I might be screwed if the CMOS reset changes the default HD boot order. If that happens, the only way to get the system to boot to the desktop would be to disconnect all other drives except for my main Mac installation?

That seems like a hassle and/or potentially dangerous, yes? I have several drives hooked up, backups, media drives, caches, etc. that I won't be able to get to?