One of the two sticks in the drawer? ;) No, ok... What's the output of
wmic computersystem get TotalPhysicalMemory
pasted in a command prompt? Or can you post a screenshot of the performance tab of the task manager?
And why do you still use v2 RC1? Just wondering...
Btw: Potentially the scene suffers from something I notice in many scenes using ForestPack/Foliage: the commit size is incredibly large. The ram usage of the max process never comes even close to the comitted ram during rendering, but the OS has to provide it. Needless deal-breaker when operating at ram limit.
Good Luck