upgraded to 10.8.5 and now have multiple monitor issues

hi all,

i recently updated my macpro (4,1) to 10.8.5 from 10.6.8. i have two monitors hooked up to the gt120, one through dvi-->hdmi cable and one displayport-->hdmi cable. both monitors have worked fine for a year or two before update.

my desktop extends across both screens just fine. however, when i open up system preferences to adjust the color of the second monitor (using the display window on the second desktop) any changes i make affect the main monitor, not the second. so i try changing color settings on the main monitor and it affects the main monitor, too. so i have no control over the second monitor's color.

i have reset PRAM, disconnected power, etc. i downloaded nvidia's latest driver. not sure where to go from here. btw - i am having other minor issues since upgrade such as my moure (wacom intuos) won't move onto second monitor; it's stuck on main monitor. my apple wireless mouse will span both desktops. i guess it's probably unrelated but since it is affected by the monitors, too, maybe it's related.

any thoughts? thanks.

macpro (2x2.26 quad)

12 GB RAM

gt 120

gtx 285

internal RAID