Q: What is virtual RAM (memory)? A: Virtual Memory is a part of your hard disk or SSD reserved for serving as RAM when RAM is full.

This can be very helpful if you have a small amount of RAM (4GB, 8GB).
Virtual Memory will be useful even you have more RAM (above 16GB) you can set a small amount as Virtual Memory.

Q: How to set?
A:

1. Open windows search then type env
2. Open Edit the system environment variables this will open System Properties window
3. Click on the Advanced tab
4. Open Performance>Settings
5. Click on the Advanced tab in Performance Options Window
6. Now click on the Change button in the Virtual Memory group.
7. Uncheck Automatically manage paging file size
8. Select C: drive in the next box
9. Click on the Custom Size radio button
10. Fill both the input boxes (initial size and maximum size) with values from the below snippet. The right amount will be just double your RAM.

4GB RAM - 8192 MB
8GB RAM - 16384 MB
For more than 16 GB you can set any amount 8192 or 16384

Now click OK and restart your computer and you are done.