There are a lot of reasons why systems slow down.
Some process might be bogging down the CPU, you may be seeing a lot of disk contention, or maybe memory is in high demand and a lot of swapping is going on. Then again, the system may be slowed down because of network bandwidth contention.
Like a busy door with too many people wanting to enter and exit at the same time, a system’s network connection can represent a serious limiting factor in how well it performs.
