Reduce colors from Millions to Thousands I was trying to run a Keynote presentation on a secondary display and Keynote told me that I didn't have enough video RAM and either needed to reduce the resolution or number of colors from Millions to Thousands.  I know how to change the resolution, but how do I change the number of colors?  

Thanks!
For some reason, the option to change color depth was removed in Snow Leopard. SwitchResX can still do it I think, but that's shareware (10-day demo).