primechecker

gistfile1.py

def isPrime(num):
	prime = True
	for x in range(2, num):
		if num % x == 0:
			prime = False
	return prime

You don't have to check from 2 to the number, just to the square root. Here's an example: 100, whose square root is 10. Whenever you have a factor, like 5, 100/5 will be on the other side of the square root, so you only have to go up until the square root to determine if it's prime.

Also, you should exit out of the loop once you've determined that it's composite, so instead of setting prime to False, return False right away, and return True at the end.

Also, once you check two, you shouldn't check four or six, as they are multiples of two, so just check for 2, then 3, then 5 ... to the square root. That halves the operations necessary to determine if a number is prime.