U welcome.
In the modules you just need to load the mlv_rec for raw and if you want sound in your raw load the mlv_snd, if you want to preview raw video in camera load the module mlv_play. Never load the mlv_rec and raw_rec at the same time. ram_rec is the first version of raw module, not have sound or metadata.
Yes, it's normal, camera cpu is slow. Thanks to the god's of ML we got preview in camera, even if is slow is just great.
Use search tab or navigate in the forum, all the questions/answers are here =))