Okay, this is an odd situation. Have a 16" MacBook Pro that I run three 4K displays off. Two are through a Thunderbolt 3 dock (one off the dock's DisplayPort port, the other off the dock's "outbound" Thunderbolt 3 port through a USB-C-to-DisplayPort cable,) the third is direct to a Thunderbolt 3 port on the other side of the MBP.
When I'm running with the MBP's lid open, all three displays run at 60 Hz.
But if I close the MBP's lid, two of the displays (the one through the dock's outbound TB3 port and the direct-to-a-port-on-the-other-side) drop to 30 Hz. The third (on the dock's DisplayPort port) stays at 60 Hz.
It's not a huge deal, I have them three-across, and the middle display stays at 60 Hz, and that's where I do things that higher frame rates are better. (Left display is "communication" - email, Discord, Slack, etc; right display is "social media" - Twitter, Reddit, etc.). But it does seem odd. I would have figured that running the internal display as a fourth display would have made it less likely to let all the externals run at 60 Hz, not the other way around!
Anyone know of a way to 'force' them to all stay at 60 Hz with lid-closed?
I should also note - all three of these displays are pretty much "first generation 4K/60" displays (Acer B286HK) that support DisplayPort 1.2 max, and are selectable between DP1.2 or DP1.1. I have them all set to DP1.2, because that's the only way they support 4K/60 at all. If I set them to DP1.1, they drop to 30p no matter what.
When I'm running with the MBP's lid open, all three displays run at 60 Hz.
But if I close the MBP's lid, two of the displays (the one through the dock's outbound TB3 port and the direct-to-a-port-on-the-other-side) drop to 30 Hz. The third (on the dock's DisplayPort port) stays at 60 Hz.
It's not a huge deal, I have them three-across, and the middle display stays at 60 Hz, and that's where I do things that higher frame rates are better. (Left display is "communication" - email, Discord, Slack, etc; right display is "social media" - Twitter, Reddit, etc.). But it does seem odd. I would have figured that running the internal display as a fourth display would have made it less likely to let all the externals run at 60 Hz, not the other way around!
Anyone know of a way to 'force' them to all stay at 60 Hz with lid-closed?
I should also note - all three of these displays are pretty much "first generation 4K/60" displays (Acer B286HK) that support DisplayPort 1.2 max, and are selectable between DP1.2 or DP1.1. I have them all set to DP1.2, because that's the only way they support 4K/60 at all. If I set them to DP1.1, they drop to 30p no matter what.