Benchmarking udoo v cubitruck v raspberry pi

Just done a little test on all my platforms, by running this python script which generates prime numbers .

Code:

#!/usr/bin/python
import sys
import math 

def is_prime(num):
	for j in range(2,int(math.sqrt(num)+1)):
		if (num % j) == 0: 
			return False
	return True

def main(argv):

	if (len(sys.argv) != 3):
		sys.exit('Usage: prime_numbers3.py <lowest_bound> <upper_bound>')

	low = int(sys.argv[1])
	high = int(sys.argv[2])
	
	if (low == 2):
		print 2,
	
	if (low % 2 == 0):
		low += 1
		
	for i in range(low,high,2):
		if is_prime(i): 
			print i, 
		
if __name__ == "__main__":
	main(sys.argv[1:])

run with :- time ./prime.py 0 1000000 > /dev/null

All running Debian 7 and very little load , No gui desktop running. ( just headless )
all standard images downloaded from the makers web sites , no extra clocking from the default image.
eg the udoo was the udoo_quad_debian_wheezy_armhf_v1.0beta image .
Cubitruck and udoo running on sata and the raspberry on a class 10 sd card.

Code:

Cubitruck 1 = minutes 29 seconds to 1 minutes 32 seconds ... run 3 times 
Raspberry Pi = 3 minutes 45 seconds to 4 minutes 9 seconds .. run 3 times
Udoo =  49.566 seconds to 49.701 seconds .. run 3 times

And that using a single core on all platforms