We substitute $x = 4$ into the expression $x^5 - 5x$ to get $4^5 - 5(4)$.
Evaluating this expression, we have $1024 - 20 = \boxed{1004}$.
The answer is: 1004
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
What is the value of $x^5 - 5x$ when $x = 4$?

### Answer:
