The difficulty you are referring to is a generic Tutu problem; I can't find the post now but there are a bunch of them that explain the whole thing in detail (it is a darned old problem that comes up all the tme
).
The short answer is turn off ambient sound in those areas. Something makes Tutu slow down dramatically when multiple ambients are called (happens in those areas.) The second thing to do (tremendously helped me!!) is to make sre you have used the Degreenifier, and turn on 3D accelleration in the configuration file in your EasyTutu folder, being careful to test it out. On my machine, the 2Q settings are way more than enough to overdo the graphics accelleration. I now have rain, thunder, ambients overlapping (outdoor+ speech + thunder/rain/wind + combat, etc. etc. and it runs incredibly smoothly (and your rig looks like it could kick my silly little old alinware 1.7GHz rig's sorry bottom
!).