Storage paging is an operating-system memory-management technique that moves less-active data from RAM to a storage device, such as an SSD, to make room for data currently in use. The moved data can be brought back into RAM when needed. Because storage is much slower than RAM, paging can make a computer less responsive, especially when memory is heavily constrained.
Paging helps systems continue running when applications need more memory than is readily available. In cyber security, it matters because sensitive information may be written to a paging file on disk, where it could persist beyond its time in RAM and be exposed if the device or storage is accessed without authorization. Attackers may also exploit memory pressure to degrade availability. Defenses include protecting storage with encryption and controlling access to the device; performance tuning that keeps more active data in RAM is not, by itself, a security control.