virtual memory
This term describes a technical abstraction where the operating system tricks software into believing there is more RAM available than physically exists. It is a critical concept in computer architecture, specifically regarding the swap file or paging file used to move data between the physical memory and the disk.
Because it refers to a specific system mechanism or a conceptual state of memory management, it is treated as an uncountable noun. You would not refer to "virtual memories" when discussing the technical capacity of a computer; instead, you would discuss the "amount of virtual memory" or "virtual memory allocation."
Meanings
A memory management technique in computing that uses a portion of the hard drive or secondary storage to simulate additional random access memory (RAM), allowing a computer to run larger programs or more applications than its physical memory would normally permit.
The system slowed down significantly because it was relying heavily on virtual memory.