Important note about factoring and CPU's

[Uncwilly]

Important note:

It is advisable now to only use GPU's to do trial factoring, not CPU's. The difference between the two is so great that it makes no sense to do TF on a CPU. If you have a CPU that is otherwise 'too slow' to do primality testing and want to put it to use to help GIMPS, consider the following tasks:

• If you have a reasonable amount of RAM, do P-1. There is always a need for that and if you get your assignments from GPU72 you won't have to worry about holding anything up. You can do P-1 with less RAM but it will take longer. Just make sure you are doing big enough bounds to make the P-1 worthwhile and not have to be rerun.
• If you can run a recent version of Prime95, run PRP-CF or PRP-CF-DC assignments. These are small enough for slow machines to show progress and help ensure that we know if there are more factors or not for an exponent.
• With the v30.6 you can do P+1 work. This might find a few more factors for low exponents.
• If upgrading the software is not doable (a remote machine for example) and RAM is not good, there are the ECM tasks.
• You can also set your machine to get as many cert assignments as possible. If you can handle the files even a slow machine can handle certs in under a day.

If all you have is a CPU and want to do TF on a special number before you run a first time check (hopefully your are doing a PRP test and going to generate a VDF/proof file), there is the option of asking for help. Someone with a GPU could knock out the TF for you while you do a task for them (like P-1 or a DC) in exchange.