I haven't gotten around to buying the K420 yet since I haven't done much photography lately but I will be testing some RED raw footage tomorrow which is 16bit, so maybe that will motivate me to actually go out and pick one up.  The K420 also doesn't support the full resolution of my monitor which would be a little annoying when editing video in a timeline as I'd be limited to 16:9. To find the True Color panel in Windows 10 go to the Windows control panel section where you'd change your resolution. Not through your GPU's control panel.  Then click "Advanced Settings" and in the new window click the "List All Modes" in the "Adapter" tab.  You should see a bunch of supported resolutions along with the Bits per pixel number and your signal refresh rate.  I see: 4096 by 2160, True Color (32bit), 50 Hertz.  Mine is limited to 50Hz simply because Display Port 1.2 only supports 60Hz up to 3840x2160. When I get a 10bit GPU and run a gradient test or NEC's 10bit test I'll post back. ... View more

I have a GTX 690 and can confirm that the 10bit setting in the Nvidia control panel only applies to Direct X games.  From further reading I believe that all version of windows actually do support 32bits per pixel and that the confusion came from Microsoft moving the True Color panel to a different menu because I've found it in Windows 10 and 32bits is selected as an option. When my Xrite i1Display calibrator comes in the mail I will go out and buy the lowest end quadro card (K420) and confirm if 10 bits will work. ... View more

From what I've read in other forums Windows 8, 8.1 and 10 don't support 10bit color.  Windows 7 was the last version known to support 10bit assuming you had a 10bit monitor, 10bit program and a 10bit GPU with OpenGL support. ... View more