I think it means that you might get better, more efficient performance if you increase the MAX Memory in the ARIA settings.  Your PC seems to have plenty and CFX is a library that can use quite a bit when it's available.  This is how much sample RAM is kept in memory before it starts doing direct to disk streaming.  The user gets control of this.

Notice that Mine is currently set to only 512mb, even though I have much more RAM installed in my PC.  I don't run any Libraries in ARIA as large and complex as the CFX Grand, so 512mb is plenty for me in most of my projects.  One can load instruments and play them while watching the 'performance monitor' to get an idea of how busy ARIA is, and how it is managing RAM.