if that didn't make any sense to you, just think that there are very fast ways that 'special' numbers like mersennes can be checked. The downside is that you can ONLY find mersenne numbers (or other similar numbers) with this special algorithm, but you can still find larger numbers faster.
This new way is an algorithm that'll find if ANY number is prime, but while it's faster than checking all the primes less than the Square Root of the number in question, it's not nearly as fast as P95 at checking mersenne numbers in the special form (2^k)1.
