I installed the latest beta & set “CoolBits” “16” in the device section of xorg.conf, but allowable voltage offset range was still 0 to 0. Is the card not supported?
Do you have access to other settings?
Have you tried with:
/etc/X11/xorg.conf.d/20-nvidia.conf
Section "Device"
Identifier "Default Nvidia Device"
Option "Coolbits" "16"
EndSection
With “CoolBits” “8” or “CoolBits” “24” powermizer works and without them powermizer doesn’t, so I think xorg.conf probably works fine for setting CoolBits options.