Under certain circumstances, the Virtual Sample Memory (VSM) feature of the EXS24 sampler in Logic Pro 7 may turn itself off. As a result, songs may use more RAM than what's available.
This happens if you disable the audio hardware driver in the Audio Drivers preferences window and then relaunch Logic Pro. If you swap one audio driver for another, VSM will remain on. Only starting Logic without an audio driver enabled will cause this issue to happen.
This document will be updated as more information becomes available.