This goes slightly beyond my level of competency but I understand that the limitations come from XP which wwill not allow a process to use more than one of the 4 CPU (ie 25% of total). So the app might run hundreds of parallel threads but will never get allocated moe than 25% CPU. Anyway speed is so great that this is not a problem.

Completely agree with the over-fitting part. But unfortunately the e-ratio does require many optimisation runs (despiet not being a proper optimisation procedure)

I most typically run AmiBroker through a virtualised XP container from within my Mac laptop, so performance will never really be peak. It’s also important to note that if you’re doing big optimisations that take a lot of time — especially if you’re optimising parameters which calculate PositionScore! — you are likely over-fitting, and less likely to have something which works in the future. YMMV.