Most laptops with any Nvidia hardware have two GPUs, one less power-hungry GPU integrated into the CPU and one dedicated GPU to play games on when you're connected to/sitting nearby a power outlet.

As good as the performance of mobile GPUs is these days, they still suck up a lot of power. I don't think you'll get much work done on the go with a laptop that only has a dedicated AMD/Nvidia GPU.

One power hungry / hot one for gaming, one low-power / cool one for when not gaming.

From my experience with Optimus in the past: The system includes two GPUs, one that sucks for gaming and another one that also sucks for gaming :)

It's probably beter nowadays, but I will never consider it again.

But from two different manufacturers?

That's asking for trouble with driver issues.

Normally the low power gpu is the integrated Intel one that's on all their consumer chips, so it's more adding one gpu than slapping in competing ones. Although it does cause driver issues anyway, hence the thread.