Default [Q] [CM10.1] Only 787MB of RAM (I already used a ram fix file)

I'm using CM10.1 on my Atrix.
As I installed it, it recognized only about 200MB of RAM, so I used a RAM fix zip file which partially fixed the problem.
If I check the amount of RAM now recognized, now it says 787MB, which is good, but with the ROM Stock it was about 815MB (about 30MB of difference).
Is this normal? Or did I use an old RAM fix file while a better one is available?