Take your 500 cores and join PrimGrid. You will have fun, you will be using the most advanced prime number software on the planet, and you won't be rediscovering primes that are already known. PrimGrid has published all of the consecutive primes up to 210,000,000,000. Compressed, the list requires 6 DVD's. Finding consecutive primes is only one of the many projects they have. With 500 cores you should make the leader board easily.
link:
PrimeGrid