Quote:
Originally Posted by R. Gerbicz
It is better to run the largest interval on one core that fits in memory. That was the reason I've used only one core for my search. (running t cores and on each of them testing interval/t primes yield the same speed with 1 core and interval primes.)

I am not sure about that. I made some benchmarks up to 5E7 using different intervals and found that the optimal interval size is
always (about) 1/1000 of the upper boundary. Though I did not check for very large values, my guess here is that there should be also some optimal value which is not using the full memory. I will do some more testing with higher values...