Macbook Pro 2018 degraded performance under load

The shady Apple practices

Recently I've started using external 4K monitor with my Macbook Pro. I was shocked to discover that the laptop is running 30% slower. That's right it's slower by third.

I've got one of the most powerful Macbooks you could buy at 2018 with i9 processor (2.9GHz with 6 Cores), 32GB RAM and Radeon Pro 560X. However that does not matter because the power is throttled. You might remember the throttling story when the laptop was released. It is almost the same now after the fix.

For example, my test suite takes 1m40s to run without external monitor. However with the external monitor it takes 2m10s. That's a big jump.