There is an issue with OXCE 5.1, "extraSounds" and RAM allocation.
i've just added ~50 ambient sounds with "extraSounds/type: BATTLE.CAT" (ogg format, about 100mb in total).
And Main menu/X-Piratez 99j8 WITH "ambient sounds 100mb" mod consume MUCH MORE RAM. ~1500+mb!
For example, OXCE 5.1 (main menu/X-Piratez 99j8 without "ambient sounds" mod) eat something like 250mb RAM
A few tweaks later (27 files in ogg format, 29mb in total):
Main menu/X-Piratez 99j8 WITH "ambient sounds 29mb" consume ~820+mb.
It would be nice to change the way it works with memory.
p.s.: Mod prototype for testing purpose (17mb):
http://spacesim.net/xpiratez/mods/FG_Ambient_1.1.zip