Hi!

you are very unlikely to need a second GPU for vMix unless you deal with very big projects or have a very old nVidia card.

Use GPU-z to monitor your GPU load. https://www.techpowerup.com/gpuz/

In case you want to have more than 2 simultaneous encodes, I don't thinh adding a 2nd card would solve this. But you can get a nVidia Quadro P4000 which works well with vMix and has unlimited encodes.

Guillaume

The Quadro range are a good option for more than 2 encodes, the confusion I think lies in their price to performance which is why we usually recommend GeForce.
For example we have seen many customers purchase a $200 Quadro thinking it is just as fast as a $200 GeForce when it is actually around half.

Comparing the number of shader cores is a good way to compare NVIDIA cards across the board.

The new Quadro P2000 is $500 for 1024 shader cores, vs 1153 on a GeForce 1060 3GB for $300

I'm curious about this because my vMix has PC (Airtop-PC from CompuLab) is specifically designed to allow the use of the GTX card AND the Iris Pro GPU at the same time.

Normally, adding the dedicated GPU card will trigger the BIOS to disable the on-board GPU. This system is designed for digital signage applications, so all six outputs cab be drive at the same time.