Some operations in c9 require more memory than c9 may have available and are very memory hungry. i.e. importing and processing high resolution Harley catalog diagrams. Normally, java's default behaviour in terms of memory is more than ample for c9's relatively modest needs. Though there are exceptions. You only need to worry about contents on this page is c9 support have explicitly directed you here.
Firstly, to check how much memory c9 allocates. Select From top menu, Terminal and the System Monitor. A window will appear in bottom left. The second number indicates amount of memory allocated. e.g. from below ~ 450 MB. c9 will comfortably run with 50Mb. Most terminals will have java allocating itself approx 120Mb or 240MB: which is more than what c9 needs for normal day-to-day usage.


To run c9 and specify amount of memory. First make sure java is not running by selecting File - > Exit and Restart java. Then put following on command line. 512m means 512 MB. Substitute this with amount of memory you want to allocate.
c:
cd \c9
java -Xmx512m -jar startup.jar
After restarting. Select system monitor to ensure memory change was applied.
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