you might also want to amend your ofp.exe shortcut that you use to start your game as follows
Right click the exe shortcut
in shortcut tab, go to target box
add -no splash -no map as in the example below;
This deals with memory issues associated with bloated addon folders.
....[X= your drive its installed on]
"X:\Program Files\Codemasters\OperationFlashpoint\FLASHPOINTRESISTANCE.EXE" -nosplash -nomap
nb, using another/second shortcut for the same mod, without the added ending above will not give you the same memory benefits.
As for memory on computer, if you have XP and use NTFS system, consider putting OFP in its own Partition, with a tool like Partition Magic.
You could also add extra ram , so windows page file/virtual memory needn't be accessed frequently.