Explanation:
Disk access is much slower than memory access. Using swap space significantly decreases (or degrades) system performance because it moves data to much slower disk storage (HDD/SSD) when RAM is full, causing delays and potential bottlenecks as the system constantly reads/writes, a process much slower than direct RAM access. While essential for preventing crashes when RAM runs out, excessive swapping leads to a condition called "thrashing," where the system spends more time swapping data than doing useful work.