I have the 15" 2017 MacBook Pro (with the four USB-C/TB3 connectors).
I recently bought this TV, which is my first and only 4K display: https://www.amazon.com/TCL-43S405-43-Inch-Ultra-Smart/dp/B01N29XPO3/
I purchased both of these cables:
No matter what I do, OS X will not recognize it as 4K @ 60Hz.
The monitor says all three HDMI ports support 4K60Hz. Both cables say they support 4K60Hz. The laptop says it can support four 4K60Hz displays. And yet there's no 60Hz.
My 4K AppleTV correctly plays 4K 60Hz via HDMI to this TV.
Much googling has been done on this subject, with only two things which keep coming up:
There's a thread where somebody finally gives up on HDMI and connects his display via DisplayPort (which I wish this had, but it doesn't)
There's a thread where people say option-click "Scaled" in the Display preferences and can select the refresh rate. When I do so, there doesn't exist a pull-down for refresh rate.
Here's the display preferences:
Here's the system profiler information:
Radeon Pro 560: Chipset Model: Radeon Pro 560 Type: GPU Bus: PCIe PCIe Lane Width: x8 VRAM (Total): 4 GB Vendor: AMD (0x1002) Device ID: 0x67ef Revision ID: 0x00c0 ROM Revision: 113-C980AJ-927 VBIOS Version: 113-C9801AU-A02 EFI Driver Version: 01.00.927 Automatic Graphics Switching: Supported gMux Version: 4.0.29 [3.2.8] Metal: Supported, feature set macOS GPUFamily1 v3 Displays: Color LCD: Display Type: Built-In Retina LCD Resolution: 2880 x 1800 Retina Framebuffer Depth: 30-Bit Color (ARGB2101010) Main Display: Yes Mirror: Off Online: Yes Rotation: Supported Automatically Adjust Brightness: No 43S405: Resolution: 3840 x 2160 @ 30 Hz Framebuffer Depth: 30-Bit Color (ARGB2101010) Mirror: Off Online: Yes Rotation: Supported Automatically Adjust Brightness: No Connection Type: DVI or HDMI Adapter Firmware Version: 7.55 Television: Yes Cinema HD: Display Type: LCD Resolution: 2560 x 1600 Framebuffer Depth: 30-Bit Color (ARGB2101010) Display Serial Number: CY8430JLXMP Mirror: Off Online: Yes Rotation: Supported Adapter Type: Apple Mini DisplayPort To Dual-Link DVI Adapter Automatically Adjust Brightness: No Adapter Firmware Version: 1.03
How do I get this to display 4K @ 60Hz?
Update: If I disconnect the 30" Cinema Display (via the dual-link-DVI adapter), I get 4K @ 60Hz. It doesn't matter if I connect it via DisplayPort to a dock or into a TB2 port on an external device, it still prevents 4K@60Hz. This doesn't make sense, especially since Apple's site says this can handle the built-in display plus four 3840x2160 @ 60Hz displays simultaneously.
Update 2: I just went back to the system preferences to select settings to verify the resolutions above, clicked back on "Default for display" and suddenly I got 4K@60Hz....