While browsing PPS Mega tasks, I saw that some took 4100 s, some 5400 s. I assumed the latter had the larger FFT size and larger k, but not so.
The 4100 s tasks had FFT = 256k, the 5400 s ones had FFT = 240k.
Here are examples of each: 4100 s and 5400 s or the whole list here.
The difference seems to be the pass1 and pass2, in one case pass1 is larger, in the other pass2 is larger. And a is either 3 or 5.
What do these parameters mean and how do they influence the CPU time in such a way that smaller FFT size means longer CPU time? Especially since the tasks with shorter run times had the larger k and accordingly larger FFT.
Primes: 1281979 & 12+8+1979 & 1+2+8+1+9+7+9 & 1^2+2^2+8^2+1^2+9^2+7^2+9^2 & 12*8+19*79 & 12^8-1979 & 1281979 + 4 (cousin prime)