Mersenne primes are primes of the form $2^n-1$ for positive integer $n$. Currently, the most widely known (and employed) software for testing large Mersenne prime candidates is Prime95, which is also the software used by the GIMPS distributed project.
Unfortunately, even though Prime95 is marketed as "free", it is not in fact entirely free. For instance, the software's terms and conditions restrict the amount of prize money that can be won when discovering primes by taking a big chunk for the profit of GIMPS.
I am interested in other fast software that is specifically designed to prove the primality of Mersenne primes (using a variant of the Lucas-Lehmer test) and is free. It would also be useful to compare such software by performance, i.e., the time required to prove the primality of a given Mersenne prime for given CPU.
What are some fast and free software to test primality of a Mersenne prime?