@all: Thanks for responses.
@BaronvonSchnitzel: Ok 512 MB is minimum but the unmodded Version ran smoothly, only stuttering in harbours.
@Beery: thanks (and thanks for the great mod,too)- good to hear that RuB (and versions stil to come) do not include graphic intensive mods. I'll try deinstalling my soundmods
@markhimov: - its true that there are bigger and longer files than the original ones. it's also true that there worth some decrease in prefomance. I ve mixed my personal compilation of favourite sound mods/files. Have to sort anew it seems.
Before starting SH3 i kill all backroundprograms using "enditall" (small prog) and I've cleaned up autostart. this helps a lot to increase system performance.
Ok now the hard part: which sounds to deinstall - in no way I will change the Alaaarm sound file, originating from "das boot". Long but immersive...