(paging slows processing throughput). The distinction is not always clear. For example, a paging system can allow main memory (primary storage) to be compressed (by paging to secondary storage), and some systems allow discardable memory for caches, which is compressible without disastrous performance impact.

Electrical power may be compressible. Without sufficient power an electrical device cannot run, and will stop or crash. But, some devices, such as mobile phones, support degraded operation at reduced power. Some devices allow for