Suspend or Sleep user session while another user is active?

Hello, is there a way to send a user session into some kind of suspended or sleep mode, for the duration of a user B logging in and using the system for their own session.

As it works now when simply switching users, the CPU and memory usage of the user-A session apparently stay active in parallel, slowing the system down considerably, even though it's fairly high-spec. (8-core i7, 16GB RAM and SSD system disk).

Id like to have all of the session A stuff swapped away on disk and the CPU activity paralysed so all resources are available to B 100 per cent during the B session, and then have the A stuff restored and user A brought back to exactly where they were before, when switching back. Is such a thing even remotely possible.

In case you're curious, user A in this case is the wife doing some research and wanting a browser window with several tabs of search results and some other bits and pieces to stay open and unchanged on her screen and be available exactly as she left it when she comes back.