That's fully expected - consider when you do multiple things at the same time, it necessarily requires separate memory. For a simple example consider if you ar

That's fully expected - consider when you do multiple things at the same time, it necessarily requires separate memory. For a simple example consider if you are editing a photo. Your photo editing application requires X amount of memory. Now you leave that running and begin editing a second photo at the same time. To do this requires somewhere between X and X * 2 amount of memory, depending on how much application state can be shared between the two instances.