Hi,
with "nv" version 2.1.10. I can't for the life of me get a dual-head
configuration to work on my GeForce 8600 GTS.
I have an 8800 GTX and I've managed to have this working for a while.
I have this in my xorg.conf:
Section "Device"
Identifier "Card0"
Driver "nv"
Screen 0
Option "CrtcNumber" "0"
Option "AccelMethod" "EXA"
Option "MigrationHeuristic" "greedy"
Option "Dualhead" "1"
Option "Randr12" "true"
EndSection
Then I use xrandr (via .xinitrc) when X starts:
xrandr --output VGA2 --right-of VGA1