RAM compatibility refers to the ability of a computer's motherboard to work with specific types of RAM modules. Each motherboard has a designated type of RAM it supports, such as DDR4 or DDR5, and a maximum capacity it can handle. It's essential to check the motherboard's specifications to ensure the RAM you choose will function properly. Additionally, RAM compatibility also involves matching the speed and voltage requirements. Different RAM sticks may have varying speeds, measured in megahertz (MHz), which can affect overall performance. Using incompatible RAM can lead to system instability or failure to boot, so always verify compatibility before purchasing.