Final answer:
Windows Memory Diagnostic and MemTest86 are tools for assessing RAM, but for simply checking the installed RAM, you can use system utilities like Task Manager, System Information, Activity Monitor or the 'free' command on Linux.
Step-by-step explanation:
The subject of your question falls under Computers and Technology. A robust tool for performing a quick assessment of the amount of RAM in a system is Windows Memory Diagnostic for Windows users, or MemTest86 which can be used for various operating systems. These utilities are used to check if your RAM is functioning correctly and to measure its capacity. However, if you simply want to know how much RAM is currently installed in your system, you can use the built-in Windows Task Manager or System Information tool on Windows, and the Activity Monitor or System Information on macOS. On Linux distributions, you can use the free command in the terminal to see your total and available RAM. Remember that while many of these tools can show you the amount of RAM, not all are available for free. Among free software, MemTest86 offers a free version that can be used from a bootable USB stick.