The key to an effective prime search is having a good sieve file. For the past several months, our primary focus has been on getting the PPS Sieve deep enough to start LLRing. While we have made great strides in this effort, we still need more help. Leading up to this Challenge, anyone with a 64 bit multiple core system is encouraged to join the Proth Prime Search sieving effort. Please see this post if you are interested.