6 Replies Latest reply on May 23, 2016 2:48 AM by amdmatt

    Can't use 75Hz in EyeFinity


      I have 3x Dell 1908FP displays in EyeFinity 3x1, these displays are capable of displaying 75Hz, but I can only choose 60Hz while in EyeFinity.

      They worked fine at 75Hz in Surround on my old GTX 760, but won't work on my R9 290X.


      I am using Crimson 16.3.2 on Windows 10 Pro x64, exact same configuration (except with a GTX 760) worked before

        • Re: Can't use 75Hz in EyeFinity

          Please provide more information so we can help.


            • Re: Can't use 75Hz in EyeFinity


              R9 290X

              Windows 10 Pro 1511 x64

              Crimson 16.3.2

              Dell 1908FP 1280x1024 @60Hz DVI-D (supports 75Hz)

              Dell 1908FP 1280x1024 @60Hz HDMI to DVI-D adapter (supports 75Hz)

              Dell 1908FP 1280x1024 @60Hz DVI-D (supports 75Hz)

              Gigabyte GA-Z170M-D3H

              Intel Core i5-6600

              Corsair TX750 (750W)

              16GB DDR4 (2x8GB)

              I can drive all three displays at 75Hz if they're operating independently, but if I enable EyeFinity, I can only choose 60Hz. With my old graphics card (Nvidia GeForce GTX 760) I could drive the same displays with the same connections at 75Hz in Surround.

              This seems to be a missing feature or a bug.

                • Re: Can't use 75Hz in EyeFinity

                  If I disconnect that display, I won't be able to use EyeFinity because I'll only have 2 displays (and that display is the middle display). I recall that same adapter being able to do 75Hz Surround with a GTX 760 (and I had checked on the monitor's OSD). I have a passive DisplayPort-DVI-D adapter which I know works, would that work if I used it in place of the HDMI-DVI-D adapter?


                  Also, I looked it up and the R9 290X has HDMI 1.4, which is capable of 1920x1080 @120Hz. DVI-D is capable of 1280x1024 @85Hz in single link.


                  Edit: I swapped out the HDMI-DVI-D adapter for the DP-DVI-D adapter. Same problem; it's not the adapter. I can do 3072x768 or 3232x768 @75Hz but at 3840x1024 or 4040x1024 I can only do 60Hz. This is either a driver problem or a high end AMD card just can't do what a mid range Nvidia card can.

                    • Re: Can't use 75Hz in EyeFinity

                      Try using an Active DP-DVI-D adapter.

                        • Re: Can't use 75Hz in EyeFinity

                          I'm fairly certain it's a passive adapter, but it works for 75Hz as long as EyeFinity is off.

                          I can do ALL THREE displays at 75Hz with EyeFinity disabled, but as soon as I enable EyeFinity, I can only do 60Hz.

                          At these resolutions even VGA could drive my monitors at 75Hz, all the card needs to do is output 1280x1024 @75Hz to each monitor.


                          Edit: Just saw something online and looked up more information about EyeFinity.

                          "AMD Eyefinity supports a maximum of 2 non-DisplayPort displays (e.g. HDMI, DVI, VGA, DMS-59, VHDCI)

                          (which AMD calls "legacy output") and up to 6 DisplayPort displays

                          simultaneously using a single graphics card or APU. To feed more than

                          two displays, the additional panels must have native DisplayPort support.[3] Alternatively active DisplayPort-to-DVI/HDMI/VGA adapters can be employed.[4]"


                          Why is this? Why can even a $130 GTX 650 do Surround at 75Hz with passive adapters and DVI?

                          I'm hoping this gets fixed with the new cards or I'm going to have to switch to Nvidia for my next upgrade.

                          Active DisplayPort-DVI adapters are expensive in Canada ($30 and it's only an adapter, no cable).