12 GB of RAM for PC gaming system is merely 200% over what is really required....; additional performance gained over 4 gb...? None.
(What does "DT" even mean, anyway?)
Put the money saved into a 2500k and Asus P67 based MB...
(I don't think you are going to find a GPU with all the above ouputs you listed these days....)
Thanks for the ifo. "DT" = desktop. The machine will also be used as a work station, as well as, video and photo editing therefore the xtra memory should be useful.