Can't get 60Hz on Second Monitor

[mdavis501]

I have a iMac Retna 5k, 27 inch, 2019. The iMac is configured with a Radeon Pro Vegas graphics card. Everything works fine.
I wanted to connect a second monitor since I do a lot of photo editing. Connected a 27 inch Asus PB287Q, using a high end type C display port connector that connects directly into my iMac and then to the Asus.

I run the Asus scaled at 3008 x 1692. Looks good.

Everything appears to work fine. When I select the Apple Menu and About this Mac and choose system report and choose Graphics/Displays, it shows that the Asus is: 6016 x 3384, "UI looks like: 3008 x 1692 @ 30 Hz" !!!

Now, the screen doesn't go dark or look bad at all, but i don't know why it's not at 60Hz.

I have gone into the menu settings on the Asus monitor and made sure I chose Display 1.2. It DOES show this. I don't know what else I should do to get 60Hz.
Any thoughts?

 

[Fishrrman]

Try a different cable.
Sometimes that's the culprit.
Or... try a different port on the display.

You didn't tell us what type of connection port you're using on the display.
What is it?
What OTHER ports might be available?

Can you get 60hz using any OTHER possible resolution?
Even if you choose it "for test purposes only"?

 

[mj_]

I don't think it's a resolution issues. In theory using a USB-C to DisplayPort cable should do the trick. I'm assuming that's what you are using. If so you may want to try a different cable because on paper you did everything right.

 

[mdavis501]

Thank you very much. I think I will try a second cable. Somewhat related -- if I purchase a LG Ultrafine 5K and connect this monitor to my imac 2019.....is it just one cable that I will need to drive the second 5K? I've heard various reports on needing 2 TB cables for connection, but there's only ONE input connector on the LG Ultrafine 5K.