>But is the res-pbo more effective
nope. It's less efficient.
the only difference between res and non res is that resistance pbo's have 'signature' entries put in them at beginning of file defining the "product = resistance pbo' !!!!
There are, occaisionally, minor differences in the last header of the file as well (a difference signature) instead of being the classical empty null, it contains the compressed signature to indicate that some/many/all of the preceding 'files' are compressed.
Encryption as such has nothing to do with 'resistance pbo's'. Some files, notably config.cpp and descritpion.ext are sometimes 'encrypted' . 1985/ Resistance, take your pick it makes no difference.
Winpbo makes a mess of these, wheras amalfi's 1.5 does everything required for ALL pbos, addons included, except occaisonally gives a misleading and wrong checksum error which can be safely ignored.