We are kind of wrapping up all our testing and working with the Apple Business Team to figure out how we move forward.
This thread is getting a little side tracked with monitors and so I wanted to point out that these issues discussed are completely unrelated to brand/model of monitors being used. That said, it IS related to having monitors connected and the internal GPU within the MacBook, along with the CPU and the overall heat that both generate.
In our final testings, we did clean installs with 10.15.2 and primarily tested an eGPU using a Razor Core and a Radeon RX Vega 64 so we could eliminate the internal GPU in the MBP.
It became really clear the combined heat from the internal Radeon Pro 5500m GPU and the i9-9880G CPU is too much for the current thermal management system, especially when using all USB-C ports. (I.e., for power, USB-C hub, USB-C to Display Port video cables). From all the testing and heat generated by the unit, it looks like our Radeon Pro 5500m GPU is fried because we are seeing artifacts on text (laptop display and external monitors) but not when we use the eGPU.
Just so you understand our configuration with the eGPU: We have one USB-C Hub connected to the MBP and one USB-C cable connected to the eGPU. The one USB-C cable to the eGPU is powering the MBP but also the eGPU has the two Display Port cable to the monitors. Now the MBP has two free USB-C ports. This was producing about 38 degrees less heat in Airflow on the MBP.
When the eGPU is connected, we can push the MBP to about 60% CPU for sustained periods before hearing the fans at about 4500 RPM. But as many of us have noticed, when we don’t have an eGPU, we’re seeing this at 5% to 10% CPU.
We have installed Parallels and ran Windows 10 on three monitors on separate space and have done Geekbench tests and a variety of stress tests with the eGPU and its operating normally.
Bottom line, the combination of using the GPU and CPU is pushing the MBP into heat conditions causing the FAN issues and in our case, possibly damage to the GPU.
Apple had a similar issue with the 2018 MacBook Pro and people were starting to stick their machines inside a Freezer to see if they could avoid the CPU’s from stepping down prematurely.
Hopefully Apple can find a solution because these new 16 inch MBP could be incredible.
Please start a support case with Apple so we can get this resolved sooner than later and it will also protect you a bit more if you need to return your units beyond the return policy. Moving forward, its all on Apple!