IDEA 8.1 Regularly Pauses for Breath

We have an issue wherein IDEA 8.1 would regularly (as in, every once in a while, and e.g. each time we press Ctrl+S) freeze for about 3 seconds. The project is quite complex and contains Spring and Hibernate facets. Also, memory consumption seems to be a bit like oil on a flat surface: it takes up all available space (currently, ~500Mb). Memory consumption seems to grow also when the IDE is totally idle.

Is there perhaps a way to work around this issue? Some configuration changes which might improve the situation?

Any pointers welcome. (Note that version 7 doesn't seem to be affected by this issue.)

Thanks!