Configuration recommendations
 

I have two Dell Optiplex 9020, both with Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz, and 8GB of memory. Both are running Linux Mint 20.1. I use both system solely for GIMPS, ie. nothing else runs on it. They are up 24x7.

Are there any configuration tips to get the most out of these system for GIMPS ? It's ok to dedicate _all_ resources to it.

1. Ensure that you're running in dual-channel mode, i.e. you have a matching pair of RAM sticks, rather than a single stick.
2. Give mprime about 6GB RAM. This will ensure good P-1 runs where it is needed.
3. Controversial - Use 1 worker with 4 threads.

You don't need to do anything particular on the OS side.

3a Test your system with 1 worker on 4 cores, 2 workers 2 cores each, 4 workers 1 core each.
3b Based upon your desire for maximum speed vs maximum throughput, choose from the above.
3b1 Consider different tasks for different workers (eg 1 worker 3 cores doing PRP, 1 worker 1 core doing P-1) as you may delight in different tasks.

0A0 Don't do LL unless it is DC.

Thank you for the suggestions.

[QUOTE=Uncwilly;582565]unless it is DC.[/QUOTE]And maybe not even then; PRP/GEC/proof/cert takes slightly less time than the LLDC + 2-4% probability per exponent of an LLTC or more also needed. PRP/GEC is far more reliable than LL even with the Jacobi symbol check, especially on systems without ECC ram capability.
There's a manual assignment category called "Double check using PRP with proof".