Woe to professionals like me daring to use dual displays on a Mac.
The macOS BigSur update is itself bad enough in taking a very long time, many minutes of which are blank (black) screens. And when it’s done, it doesn’t beep or notify, it’s just an interminable black screen. I only figured out when it was done by checking every few minutes—it had booted up and gone into sleep mode.
That dog-poop user experience aside, the real nightmare is the 45 minutes I spent trying to get my dual display setup working again, a witchraft and voodoo affair involving:
- 4 reboots
- black main screen and black 2nd screen
- black 2nd screen and lit-up main screen
- lit-up main screen and black 2nd screen
- flashing out of sync flickering problems.
- warnings of outrageous syncing settings by the display—looks like a video card that can't do things right.
Do things work better if all displays are Thunderbolt? Not realistic for professional use.
By comparison, my 2nd display on my iMac running macOS Mojave works flawlessly for 10 years (various Macs). And it and its predecessors works flawlessly for a decade or more in total.
I have no way to separate whether the issues are pure software or hardware only, or both. I just know that the same display works flawlessly on my 2019 iMac 5K with macOS Mojave.
Ron Y writes:
I have a mac pro 7.1 with a Vega two card. I am using OS 10.15.7. I have two Eizo 2740 displays both running at scaled 2560 x 1440. They work perfectly—lighting up after sleep and reboot -- all open windows returning to the correct places. My experience is that the connection type seems to make a difference. My main monitor is connected to the video card Thunderbolt and the display port on the monitor. The second display is connected using Thunderbolt connection on the top board (one that USBC and Thunderbolt connections) and Thunderbolt on the monitor. [diglloyd: it's USB-C on the display, not Thunderbolt]
Some time ago, I tried using a Thunderbolt hub and had all sorts of disasters, similar to what you are describing. You might try connecting your monitors to the computer differently. In my case, that was the trick. Hope a different set of connections solves your problem.
MPG: the Eizo 2740 display supports USB-C and USB power delivery. It is also a 4K display. As such, it is not comparable to an NEC PA302W, which is about 5-year-old tech (but still the best panel available IMO).
The ColorEdge CS2740 features USB Type-C connectivity with 60W of power delivery. With a single USB Type-C cable, you can display video, transmit USB signals, and supply power to a connected device such as a smartphone or notebook PC. Simply plug in and get creative without worrying about additional cable clutter.
Basically, we are comparing apples and oranges here vs the NEC PA302W, which supports a wide variety of inputs (except Thunderbolt/USB-C) and a very wide range of input resolutions and sync rates.
Even if I had the funds for expensive new displays (I don’t), thing is, no panel on the market today has as neutral a backlight as the NEC PA302W with its truly neutral GB-R LED backlighting*. And nothing that ppi at 2560 X 1600 resolution. I don’t want inferior color and higher ppi and inferior “looks like” resolution (eg 1920 X 1080) on the Eizo 2740.
Some time ago I discusssed those USB-C to DisplayPort cables—total fail when I tried it. I’ve tried all viable options for the PA302W, meaning dual DisplayPort adapter, Thunderbolt Dock, USB-C to DisplayPort. The first two work with voodooo, the USB-C to DisplayPort cable fails outright. HDMI is not viable for optimal calibration. There are no other options.
It is also possible that NEC displays are troubled by newer Macs, and that other brands are not. But without comparing comparable technology, that’s a dubious premise. But the most damning evidence is that this all started around November 2019, prior to which operation had always been flawless.
* All other displays I’ve tried have a slight magenta tint which measures neutral, but is definitely not neutral as any side-by-side proves including other NEC displays. I have exceptional color discrimination, so most people cannot see the tint I can see. However, I have not seen the latest crop of displays and I don't know how the Eizo 2740 behaves. It uses some kind of “Wide-Gamut LED” and maybe that addresses the neutrality issue.
re: Display Connections for HDMI/DisplayPort Displays on 2019 Mac Pro or Other Macs
re: Mac mini has Serious Trouble Syncing with Display via either HDMI or DisplayPort
re: Nasty Surprise with Apple Software Update: NEC PA302W will no longer Work (UPDATE: how to fix it)