I have the 16" MacBook with the defective Radeon 5500M GPU and have the standard power draw / fan noise / overheat problems. I disabled Turbo Boost on the CPU (with Turbo Boost Switcher Pro), and have it enabled automatically for select programs only. Clamshell mode helps, but I wanted to keep the lid open.
So now I use a DisplayLink USB dongle or dock to completely bypass the Radeon GPU.
These are a few options out of many:
WAVLINK USB 3.0 and USB-C Dual 4K Display Laptop Docking Station,5K/Dual 4K @60Hz Docking Staion Dual Monitor for Windows and Mac,(2 HDMI & 2 DP, Gigabit Ethernet, 6 USB 3.0,Audio)
www.amazon.com
This dual-4K docking station offers wide flexibility in setting up your workstation, working with both USB-C and USB-A port laptops and supporting multiple combinations of Ultra HD 4K DisplayPort and HDMI monitors. Enhance Productivity with Dual-4K 60Hz Video Ideal for highly detailed graphics ap...
www.amazon.com
The Plugable USB-C Dual 4K DisplayPort adapter allows you to connect up to two additional displays that support up to 3840x2160@60Hz resolutions each, as well as a gigabit Ethernet port. Our adapter is compatible with most modern Windows laptops, desktops and tablets that have a USB Type-C or Thu...
www.amazon.com
The Plugable USB-C Dual 4K HDMI 2.0 adapter allows you to connect up to two additional displays that support up to 3840x2160@60Hz resolutions each, as well as a gigabit Ethernet port. Our adapter is compatible with most modern Windows laptops, desktops and tablets that have a USB Type-C or Thunde...
www.amazon.com
Performance Featuring the DisplayLink DL-3500 chipset, the Plugable UGA-2KHDMI graphics adapter lets you connect an additional HDMI display up to 2560x1440@50Hz (lower resolutions at 60Hz) to your Windows-based laptop, desktop, tablet, or Mac 10.14+ systems via USB 3.0 to enable multitasking with...
www.amazon.com
WAVLINK USB 3.0 to HDMI Display Adapter,4K Ultra HD Video Graphic Adapter with Audio for Multi Monitor up to 3840 X 2160,DisplayLink Chipset DL5500,Support Windows 10/8.1/8/7
www.amazon.com
or anythink with a DL-6000 series chipset
Where to buy DisplayLink productsDisplayLink technology appears in a wide range of products from the world's leading PC and peripheral brands. It features in docking stations, monitors, adapters, and more.Products with DisplayLink technology are supported on Windows, macOS, Android and Chrome OS...
www.displaylink.com
I can play light games like AoE2 DE at native 1080p@60Hz, with a 4K and a 2K monitor attached to the Stardock displaylink dock, and this completely avoids the heat and power draw problems. Power consumption is 15-50 Watts. Radeon High Side is at 0 Watts. No need to pay for an expensive eGPU or the 5600M, unless you need 4K HiDPI @60 Hz resolutions or do graphically intensive tasks.
(I'd have no problem paying for the $700 Radeon 5600M upgrade, but I do not want to reward Apple's incompetence... Especially since they blocked Nvidia and I cannot use my $3000 Titan V eGPU for CUDA.)