The operating system will consume significant resources itself. For example, Windows 10 requires about 20GB in storage to run. In Windows, you can check to see what resources the OS is consuming by clicking Settings > System > Storage > This PC (C:) > System & reserved
Windows Virtual Memory
There is a Windows operating system feature called Virtual Memory which helps increase system performance by offloading tasks from your system memory to your hard drive. Virtual Memory can consume a significant amount of storage. By default, Windows sets the Virtual Memory size to match the size of your memory.
Note: Virtual Memory is not related in any way to Paperspace itself and behaves the same in a virtual/local environment.
The feature can be modified to consume less storage or deactivated entirely (not recommended). To adjust the settings, type system into the Start Menu and click Advanced settings on the System page.
Under the Advanced tab, click Settings and then Change under the Virtual Memory section.