iMac 5K 27" late 2015 and Dell UltraSharp U4919DW

[Kudo]

Hi there,

I just recently bought the Dell UltraSharp U4919DW and ordered a Mini DP to DP 1.4 cable (https://www.delock.com/produkt/84927/merkmale.html) afterwards. When connect the iMac to the Dell I get the following output.

But when I connect it to my MacBook Pro 13" Late 2013 it works just fine. Any idea why this happens and how to fix it?

 

[minik]

What version of macOS is on both computers? It looks like resolution issue?

 

[StandingGoose]

From the technical specs at https://support.apple.com/kb/SP731?locale=en_US

• Simultaneously supports full native resolution on the built-in display and up to two 4096-by-2160 external displays or one 5120-by-2880 dual-cable external display

 

[Kudo]

From the technical specs at https://support.apple.com/kb/SP731?locale=en_US

• Simultaneously supports full native resolution on the built-in display and up to two 4096-by-2160 external displays or one 5120-by-2880 dual-cable external display

Oh, so would a solution be to use 2 x thunderbolt 2 -> HDMI? And can I get the native solution in 60 Hz that way?

 

[Kudo]

What version of macOS is on both computers? It looks like resolution issue?

Both runs the Big Sur beta, so shouldn't be a difference there.