MaxMemToUseMB controls the size of the memory buffers that dtSearch can use to sort words during indexing.

If MaxMemToUseMB is zero, dtSearch will decide the amount of memory to use based on the estimated amount of text to be indexed and the amount of system memory available. 

If possible, dtSearch will use memory for all sorting operations; otherwise, some disk-based buffers will be used. For large updates, some disk-based sort buffers are always necessary and there is little benefit to MaxMemToUseMB values above 512 (32-bit) or 2048 (64-bit). 

MaxMemToUseMB does not affect other memory that may be used during indexing for other purposes such as parsing document formats.