I have three Dell 32" 4K monitors which I hooked up to my new GTX 970. When I run the system under windows, the card drives the three monitors in full 4K @ 60Hz mode. Very nice. When I run the system under linux using the latest nvidia driver 352.21, it will only drive two of the three monitors. Here’s the deal, when running the Dell 4K monitor in at full resolution, you need to have the monitors running in display port 1.2 mode. (dp1.2) This causes the monitor to actually behave like two monitors with each half of the monitor running at 1920x2160. So the nvidia driver will then tell you you have 2 “virtual” monitors per real monitor. So with three Dell 32" 4K mointors, I have a totoal of 6 “virtual” or half monitors. We’ll here the deal, in linux, the driver will allocate 4 of these half monitors to one GPU and if I need to drive the other two half monitors, I have to use base mosaic mode. In order to use base mosaic mode I need another card. In short the GTX970 (and I suspect all cards which have 3 dp ports) will drive three 4K monitors in dp1.2 configuration under windows but only two under linux. This really sucks…
So, Nvidia, can you confirm that under linux the driver will only support 4 monitors per GPU?
Also, if I get another card, will base mosaic or SLI mosaic work under with the GTX 970 or do I have to have a quadro class card as I’ve seen several posts on the internet indicate?