1080 ti unusual memory usage

[Alex_M]

I observe some unusual memory usage on my 1080 ti with 3ds Max. The card is not connected to any displays and I use it only for rendering. As soon as I start Max the card's RAM suddenly spikes from 192 MB to over 540 MB, while my other GPU (GTX 980), that I actually use for the viewport and 2 monitors are connected to it, go only to 480 MB RAM usage inside Max. Why does that happen when the 1080 ti is not the GPU that drives the UI, viewport and my monitors?