Affect is a verb that means to influence. Effect is a noun that means a result. Effect can also be a verb that means to accomplish, to complete, or to bring about.
Affect
Effect
The number of applications that run simultaneously can affect system performance.
The number of applications that run simultaneously can have an effect on system performance.
One effect of multiple applications that run simultaneously is slower system performance.
To effect a change in system performance, you must close one or more applications.
