Quote:
Originally Posted by windowfrog
So the PRPCF test would try to find cofactors of an exponent that’s already a known composite? Does that have a higher success rate than ECM?

PRPCF tests the nontrivial cofactors to see if they are prime. If they are, we know that the Mersenne number is fully factored. If not other testing can be employed to find factors.
ECM is one of the tests that is used in sequence to try to find factors of a number. It is not as likely to find a factor for a number as TF or P1 (which are done first in that order). But, it is searching a larger area. The task size that is handed out is small.
Quote:
For the P1 test, how much RAM is needed?

4 GB is plenty
Quote:
If the P1 test only finds factors/cofactors, would it make sense to run PRP tests on the really big numbers on the newer laptop, while searching for cofactors on the old?

Just to be clear, there is PRP for First Time checks (this is preferred over LL now). PRPDC to follow up on those that had a PRP as a first time. Then PRPCF, these are working through the lower ranges of numbers.
You will have to find what works for you on your machines. The newer laptop should be ok for first time PRP's. If you find that doesn't work, then P1 or running DC's is the next best use.
Your machine, your joy, your choice.