SFC

SFC is a straightforward command-line utility that allows you to compare a base with a target directory, as the name implies - Subdir File Compare. It can be easily handled, regardless of the user's experience level.
While most users prefer an application with a standard interface and easy-to-navigate layout, some individuals find it more comfortable to work with a command-line console, since a few key commands get the job done in no time.
So, SFC checks all the files from the base folder (including the ones found in subfolders) and tells you whether they are the same as the ones in the target location. What must be mentioned is that the app ignores any time or date differences.
The simple-to-use application does not interfere with the runtime of other currently running processes, since it requires a very low quantity of CPU and system memory.
It has a good response time and worked well during our evaluation, without causing the operating system to hang, crash or pop up error dialogs; we have not come across any issues throughout our testing.
All in all, SFC represents a very good solution to comparing the files of two directories. However, it cannot synchronize the contents, so you shall requires another application for this task, such as FreeFileSync. On the downside, SFC is not very resourceful and has not been updated for a pretty long time.