Why is swap seen as bad for hardware?
Why is swap seen as bad for hardware?
SWAP storage serves as an extra memory layer for traditional storage. While it’s noticeably slower than regular RAM, it can still be a viable option when handling memory-heavy applications that require significant in-memory space but aren’t strictly performance-sensitive. Many sources highlight that swap negatively impacts hardware performance, particularly on SSDs. Why does this matter? It’s not just about the formatting—it’s about how the system interacts with storage under load.
SSDs can only endure a certain amount of writes. Because their data often changes frequently, swapping involves storing many files, which might reduce the drive's life.
The issue with using swap arises because it demands high intensity compared to the drive’s usual purpose. Working memory gets constantly overwritten, unlike storage which can be refreshed less frequently. For storage, "regularly overwritten" means a few times daily or weekly, whereas memory needs this process much more often—sometimes every minute or hour. This level of activity is far beyond what storage drives are designed for. Still, swap isn’t inherently harmful, and if the operating system is efficient, it won’t move active memory to swap unless required. Swap should ideally be reserved for memory that isn’t being actively used, such as background processes doing nothing. However, this isn’t guaranteed.
It's acceptable but not perfect, leading to significant hardware strain. For large data volumes where RAM costs exceed storage expenses, swapping helps increase capacity but is slower than RAM. Programs handling these tasks typically store lookup indexes in RAM and rely on storage for file access instead of keeping everything in RAM—avoiding the older method of storing all data in RAM without using HDDs until needed. With NVMe technology, speed has improved (Gen4 and DDR3 match in MB/s), but CPU requests to the SSD and subsequent data retrieval remain slower than RAM. Progress is coming, and GPUDirect storage marks a shift toward reviving swap functionality. Eliminating intermediate steps between storage and CPU or GPU always boosts system performance, provided the storage can keep up. The RAM versus NVMe debate may soon intensify, with system memory potentially evolving into on-chip caches rather than separate components.