High Memory usage

I suggest you actually read the online help on how AE works, what caching is and how to configure the options. Aside from the crashing, everything sounds perfectly normal. AE is memory-driven and longer compositions/ clips simply mean more memory usage and more caching. The crashes could simply be caused by outdated drivers, an unsuitable audio configuration or the footage being malformated/ damaged.

Mylenium

Ya lo dijo Mylenium, no hay nada raro con la cantidad de RAM que After Effects está utilizando. De hecho, yo diría que Ae está bastante educado por el momento pues siempre está hambriento de memoria RAM.

Without any actual system information nobody can tell you much, anyway, and according to your screenshot AE is only using a measly 2 GB, which by all standards is not much. The only thing suspicious is the "Migrate Settings" utility, so you may want to terminate that process/ find the dialog window and finish it. If you think something else is wrong you need to explain in more detail and provide the pertinent information.

Mylenium