7680x4320 detailed 8k resolution

[ToastyX]

You can't add resolutions greater than 4095x4095 or 655.35 MHz pixel clock with EDID detailed resolutions. You have to add it in a DisplayID extension block or as a TV resolution in a CEA-861 extension block, but that won't help because it doesn't make sense to add a resolution that the TV already defines. Where is the original extension block? You are missing the data blocks required for HDMI 2.0 to work, and the original extension block probably contains the 8K resolutions already. Also, 7680x4320 @ 25/30 Hz requires HDMI 2.1, which the GTX 1000-series doesn't support, so I don't know how it's working on the other two machines unless it's set to use YCbCr 4:2:0. HDMI 2.0 is limited to 600 MHz pixel clock, but YCbCr 4:2:0 uses half the bandwidth, effectively allowing up to 1200 MHz. For that to work, it has to be added as a 4:2:0 resolution in a TV resolutions data block with "4:2:0 resolutions" enabled, if NVIDIA supports 4:2:0 with 8K resolutions.