I'm currently using a late-2013 27"iMac with a GTX775m graphics card and El Capitan OS. I'm considering purchasing a 10-bit external display to use with the iMac to edit photographs . Will this machine support 10-bit colour on the external monitor or will it be a waste of money? Should I rather get an 8-bit monitor? El Capitan seems to have introduced 10-bit support but I'm not sure if my nvidia graphics card supports 10-bit external monitors. Thanks for the help.