Custom Resolution Utility (CRU)

[ToastyX]

(11-22-2022 05:26 PM)Firsh Wrote:  Hope someone can help me. I have a Club3D CSV-7220 MST HUB that converts my single 4K-capable DP 1.2 port to DP+HDMI. I have an optical HDMI 2.1 cable, but recently the 60Hz capability stopped working and it only offers 30Hz. I have a feeling CRU could force it but I'm at a point with my trial and error that I'm getting used to the 30Hz.

I had to create a custom resolution in AMD software since Day 1 and that used to work. Now I can't even create this as it says not supported.

I tried and failed:
- Changing from 4K TV to 4K monitor (that works at 60 via DP just fine through the same MST HUB).
- Tried other HDMI cables (but I guess they could be just old standard)
- Other computer (I'm not sure if my old laptop can output 4K60 at all)
- Firmware upgrade the tv
- AMD Driver update
- Restoring Windows11 partition to a backup to when it was okay (no joy - could this mean something broke on a hardware level?)
- Contacting Club3D support (they asked for dxdiag data and blamed the cable)

One thing I notice is that the pixel clock seems to be limited to 300 whereas it would need to be closer to 600 to work no? Can I unlock it, given that the specs of the cable, displays, the Club3D device all support it? Something just makes the proper values not discoverable or recognizable by the software for some reason.

Also, isn't the point of CRU to create potentially unsupported combinations to see if they work? Hence the 15s countdown in Windows that reverts stuff? The TV is capable of telling me "unsupported format" but I can hardly ever reach that message.

CRU can't force anything if there's a driver or hardware limitation involved. CRU can only add resolutions within the available bandwidth, and the TV should already define the correct resolutions, so there would be nothing to change.

Something is causing the bandwidth to be limited. Use CRU to export the EDID for the TV to a file and attach it here so I can make sure the TV is reporting the correct information.

You mentioned testing the PA279CV with DP but not HDMI. The PA279CV has HDMI 2.0. The easiest test would be to see if the PA279CV can get 3840x2160 @ 60 Hz with HDMI through the hub.

Also, are you using one display at a time? The R9 390 only has DisplayPort 1.2, so it doesn't have enough bandwidth to drive two displays at 3840x2160 @ 60 Hz through one port without reducing the chroma to YCbCr 4:2:0, which I'm not sure if the R9 390 supports through DisplayPort.