Originally posted by Joe O

There are many opinions on the 43,3 which is sievebitdepth,PRPsaved

Adjust them to get the B1 B2 you want.
I thought like this until I got 'snubbed' by prime95.
In fact, the values represent the depth until which has been already sieved, and the number of PRPtests which will be saved by the factor.
On the base of these (and the memory allocated, and ???), prime95 calculates the optimal bounds for factoring. To tell the truth, I don't know exactly in which way optimal, but I guess for througput.

Sieving is somewhere between 2^49 and 2^50, so, 49 is the appropriate choice. A factor will save 2 PRPtests, so it's 2.0.
Putting the right numbers will be the most efficient on the long run. If you have other priorities, like the ambition to get lage factors, you can increase the bounds. But as for the project, Pfactor=k,2,n,1,49,2.0 should be the right choice.

I factored with 1.6 instead of 2.0, a while ago, too, in order to have more tests done. So... you see.

H.