Hey guys, i just wanted to let you know that i'm also facing something similar
I'm using a linux box, with BB strategy and 4 pairs running.
I am also seeing a huge increase in both CPU and RAM consumption.
I was running up to 16-20 pairs with previous releases, without issues and having multiple other programms & VR desktops running at the same time.
I'm testing ver 3.1, so i've kept the default settings as provided, changed only max btc for each pair.