Performance SWI-Prolog 8.3.5 vs YAP 6.5.0

[swi]

@jan

nreverse 92 269 273 292,39% 296,74%

Interesting that nreverse is 3 times slower in swi.
Do you have an idea why this is?

EDIT: Since it is only 30 integers, probably most of the cost is in some kind of initial setup for the call.