External Monitor low performance when connected to Macbook Pro

[tomg101]

I have recently upgraded my external monitor to the Dell Ultra Sharp 40 WUHD. (Previous setup working fine on 34 inch version U3415W, connected to Dell WD19-130W Docking Station via HDMI)

I have connected it straight from my Macbook Pro via Thunderbolt/ USB-C 2. The issue I'm having is after selecting the right size resolution in display settings (where I have looked at all resolutions, having "shown all") , the mouse movement is very laggy and resolution quality not great. The default display is not, but everything is too large on the screen, and other resolutions are either too small/ squashed or movement lags.

So my first question is, does anybody have a solution to this? I can't seem to find an answer other than trying a different Thunderbolt cable which I don't want to do if not needed or it's not going to work anyway.

Secondly, if I connect the Thunderbolt/ USBC-2 to my Dell WD19-130W Docking Station the screen doesn't recognise the signal and turns off, I've also tried DP connection and again it doesn't receive a signal. The display link app says "No Display Link-enabled display attached", is there anything I can do to get either of these things recognised?

Thanks in advance

[rboerner]

Originally Posted by tomg101

I have recently upgraded my external monitor to the Dell Ultra Sharp 40 WUHD. (Previous setup working fine on 34 inch version U3415W, connected to Dell WD19-130W Docking Station via HDMI)

I have connected it straight from my Macbook Pro via Thunderbolt/ USB-C 2. The issue I'm having is after selecting the right size resolution in display settings (where I have looked at all resolutions, having "shown all") , the mouse movement is very laggy and resolution quality not great. The default display is not, but everything is too large on the screen, and other resolutions are either too small/ squashed or movement lags.

So my first question is, does anybody have a solution to this? I can't seem to find an answer other than trying a different Thunderbolt cable which I don't want to do if not needed or it's not going to work anyway.

Secondly, if I connect the Thunderbolt/ USBC-2 to my Dell WD19-130W Docking Station the screen doesn't recognise the signal and turns off, I've also tried DP connection and again it doesn't receive a signal. The display link app says "No Display Link-enabled display attached", is there anything I can do to get either of these things recognised?

Thanks in advance

Based on the information available online, the Dell docking station you are using does NOT have DisplayLink technology inside. As a result, DisplayLink will not be able to help you in regard to the behavior of the docking station.

You don't mention the specific model of the display, however based on your description it sounds like you are using a Dell U4021QW display.

Presuming for the moment that information is correct and in regard to the display's behavior when directly connected to the host, based on your description of the behavior it sounds like macOS is not enabling a 'HiDPI' mode for resolutions other than the display's native resolution of 5120x2160.

Presuming again that is in fact the cause, there may not be a workaround.

If this were my display, I would first suggest making sure that the latest firmware for the display is installed and also install the Dell Display Manager Application for macOS to see if that helps change the behavior --> https://www.dell.com/support/home/en...onitor/drivers

If that does not help, I would suggest contacting Dell for assistance.