Max pixel clock is reported wrong, unable to fix it or change it

[jka]

Hi,

I have "Sony GDM-F520" CRT monitor hooked up to "Geforce 1080ti" GPU through "Sunix DP-3000" DisplayPort>Analog adapter. The built-in DAC on that adapter has like 500-550MHz pixel clock limit.

The monitor info is detected fine as Sony F520 but the reported max pixel clock is only 220MHz. This used to work fine for me with Sony FW900 before, I was able to reach 500MHz resolution modes. But with this new monitor it is stuck at 220MHz.

I have tried changing this value in CRU and selected "Include if slot available", restarted video and even the whole computer. I can see the new value is remembered by CRU but the artificial limit of 220MHz is still in effect somehow from somewhere.

I can add resolutions beyond 220Hz limit via NCP but that way I cannot use DSR and I often lose signal after a few minutes so the screen shuts off. There is no such random signal loss using built-in resolutions, only with high resolutions added via NCP.

Would you have any ideas what I can try to overcome this? Thank you

[ToastyX]

That's strange because I don't remember NVIDIA's driver ever listening to the "max pixel clock" in the range limits. If you can't override that with CRU, then you would have to bug NVIDIA to fix that, or use a hardware EDID emulator. Maybe you can try a cable with the DDC pins cut to prevent the EDID from being transmitted and see if that allows you to go higher. I don't know if the Sunix adapter provides its own EDID in that case. Try plugging in the adapter without the monitor to check if it provides a default EDID.