On Mon, 15 Apr 2019 15:04:16 -0000 (UTC), "Yes"
wrote:

I just saw an ad for an ASUS monitor showing 9 monitors in a 3x3 matrix
being used to show a picture. It got me curious.

Other than the monitors themselves, what hardware would be needed to do
that? For example, would something like that need 9 graphics cards,
one for each display? Instead, is that done using a specialized card?
Does it require custom software? Does it require high-end CPUs and/or
massive amounts of RAM? Or are there specially made electronic devices
produced to do that?

I don't know about running nine screens but I run four on my PC, using
two off each of two graphics cards. So far as the OS is concerned,
there is just one screen. The drivers sort it all out.