The same using python / Rhino common takes 1.1 seconds (using the brep lists variant of Boolean difference) So my guess is that the current SolidDifference tool in gh uses the first implementation of BooleanDifference. Could well be the same with SolidDifference, I haven’t checked yet
So this solution is actually much faster than the built in solid difference. the one that took 43 seconds takes 2.8 seconds now for substracting 24 objects from the original solid. But still it is slower than Rhino, the python version takes 1.8 seconds with only one object