Presuming the cash register monitor is set up as a second monitor to the BI PC and as an "extended", not duplicate monitor, you could do what works for me: In the BI desktop user interface right click on the camera(s) you want to view on the second monitor Select "+ Add New Camera&quo...

There all sorts of things that can be done, cameras can be dragged and resized, the clips window can be moved from one side to the other by double clicking at the top of it. Start in the help file under Introduction, User Interface to see if that doesn't get you what you're looking for.

Yesterday I would have said absolutely but today it's behaving as I would expect (except for a little extra effort to invoke the reply)

In Blue Iris (not camera) Settings under the Cameras tab there is an option to Limit Live Preview frames per second. Mine is set at 20 fps. You might want to play with that a little bit to see if it makes a difference. There are a boatload of tips for limiting CPU usage in the help file - under Admi...