Compatibility is an indication that a product meets some or all of the specifications for a particular standard. For example, if a program is IBM compatible, it can run on any Dell, IBM, Hewlett Packard, or other computer with that same set of Windows-compliant components. Apple computers that utilize the macOS X operating systems are not IBM compatible.
Although macOS is not IBM compatible, Bootcamp can be installed that allows it to run many IBM compatible programs.
If hardware is incompatible with your computer, you can still connect or install it, but may damage the computer. However, it is most likely the computer won't work until the incompatible hardware is removed. For example, if you install memory in your motherboard that's incompatible, your computer won't boot or displays an error as it boots.
Computer software that's incompatible with a computer (does not meet the system requirements) cannot run on a computer, generate errors, or runs slow.