Thunderbolt 4 Dock (Mercury) - How to get dual 4k 60hz displays (scaled) to work | Razer Insider

Thunderbolt 4 Dock (Mercury) - How to get dual 4k 60hz displays (scaled) to work

  • 7 October 2021
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Hey I recently received the TB4 dock ( ) but I cannot get it to drive both of my monitors at 4k/60hz when they have scaled resolution. Am using a 2016 Intel MacBook Pro. Both of the monitors only have DisplayPort connections (and HDMI), no TB3 or USB-C. I have 2 USB-C to DisplayPort 1.4 bidirectional cables (supposed to be 'active', idk) which are plugged into the TB4 ports of the dock and go to the monitors. One of the monitors is getting 4k60hz and the other is getting 4k30hz. The internal monitor is off (lid closed). I've tried to reset the SMC (= no improvement). There were no issues using direct cable connection with any type of USB-C to DisplayPort cable to get 2x 4k60hz when connecting directly to the MacBookPro.

Have attached a screenshot of my System Report's Displays/Graphics panel.
For some reason it thinks the monitors have resolutions of 6016x3384 when both are 3840 x 2160.
Am using scaling in the System Preferences > Displays. Interestingly, if I turn off scaling (or set it to max resolution), then for that monitor it correctly says 3840x2160 and performs at 60hz (along with the other, still-scaled monitor, also at 4k).

Anyone experience anything similar? Is there some MacOS settings perhaps I need to adjust for more performant scaling?

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Update -- resolved for time being at least ---

If I set System Preferences > Display > Scale to different resolution for the 30hz monitor - including a higher one, I get a similar effect of higher resolution in the System Report, but 60hz works.. go figure... then turned it back to the scale I wanted and 60hz is working as expected - awesome!

Will check later after next disconnect/reconnect to dock if issue returns. I did update one of the USBC->DP cables from a 1.2 to a 1.4 recently and this Scale toggle may have helped the dock/mac detect it.. but then again I did restart and do a SMC reset with it..