MacBook Pro freezes for several seconds when connected to two external monitors

16-in 2019 intel MacBook Pro heat and performance:

This computer was built with a ninth generation 14nm Intel processor. The only way to meet the target performance was to make it a six or eight core processor. This processor generates an enormous burst of heat when it does Turbo Boost, and there is only one cooling rail shared by both the CPU and GPU. So getting Either side too hot ramps up the fans.

This processor was supposed to be an eleventh-generation 7nm processor, but intel is three years late, and is only starting to ship its tenth generation 10nm processors now.

The drive in this computer is more than 100 times the typical speed of computers a decade older. It is the "Muscle Car" of notebook computers. If you have installed software that wastes computer resources on a regular basis, such as third-party Virus Scanners, speeder-uppers, Cleaner-uppers/Removers, Optimizers, third-party file Sync-ers such as DropBox, OneDrive, or GoogleDrive, or a VPN that you installed yourself, it will do busywork at previously-impossible speeds — heating up at a ferocious rate. This older junky software used to run as fast as it could, then would then have to wait for the disk drive to continue to waste resources. with really fast drive, that drive restriction is gone.

Apple DID redesign the cooling system for this specific Mac. New, high-efficiency fans are used. But for some uses, that is still not enough.

Some of the best advice is to install Turbo Boost Switcher and turn off CPU Turbo Boost. This reduces the huge sudden overheating brought on by Turbo Boost, that simply does not translate into real-world performance gains.

For external displays, changing away from HDMI to DisplayPort family (or to DisplayPort over ThunderBolt or USB-C) will reduce the Voltages and slightly reduce the heat generated. It is a good thing to do, but it may not be enough to solve this issue by itself.

Refreshing the information on the displays, especially the cursor position, is done at low priority the background. When the CPU is very busy, the screen may lag and even seem to freeze.

You can use Activity Monitor to see if your CPU power is being hogged by any task in particular. This article is one page from an Activity Monitor guide:

View CPU activity in Activity Monitor on Mac - Apple Support

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Do you have any of:

third-party Virus Scanners, speeder-uppers, Cleaner-uppers/Removers, Optimizers, third-party file Sync-ers such as DropBox, OneDrive, or GoogleDrive, or a VPN that you installed yourself ??

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You reported that your Mac freezes so badly your displays go dark.

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