In the first place, thanks for the hard work, Tonymac team.
I installed El Cap on a spare SSD with Clover in legacy mode(using an USB3 port)
I got this on booting from the SSD:
Boot failed with P-State Stepper Error 18
This was fixed using this tip:
Disable CPU EIST in BIOS (Z68X-UD3H-B3)
Haven't copied my DSDT or SSDT from Chameleon.
Geekbench looks OK(best results are still from my SnowLeopard days)
What works: Graphics(6870) on first DVI port, firewire(startech card), eSATA. What definitely doesn't work: USB3. My Nec/Renesas chip is the culprit, I understand.
Don't know about the builtin audio, HDMI, Bluetooth or WIFI. Don't use these. Sleep doesn't work, graphics/monitor will not wake up. Sleep has never worked properly, BTW.
USB has always been a bit flakey on this board too, USB3 worked OK for disks since Mountain Lion, but not so much for pen drives. I will loose my kbd and/or Powermate on booting sometimes. Replugging will not always work.
For work, I will stay on 10.9.5 for a while.
Gigabyte Z68XP-UD5/AMD6870/16 GB RAM/SSD's/Startech FW Card