Avenview HDMI 4x4 Matrix Switcher with 2x2 Videowall and Audio Support

This switcher can be configured in a few different ways. In picture-in-picture mode this switcher will allow you to have 4 different signals on 4 different monitors. So you could connect 4 computers, assign each to a screen and display 4 different PowerPoint slides that way. You can also set this as a 2x2 Video Wall. That means you would have a signal from one source spread out over the 4 screens. PowerPoint will not allow you to show 4 slides at a time, so you would need to create a custom slide or image that has 4 slides on it and make sure you have it appropriately sized and positioned on the screen.