property SaveMemoryLimit: Int64; // default 64 MB
Save staging keeps its working copy in memory up to this many bytes and spills to a private, delete-on-close temporary file beyond it. The default is 64 MB
Raising it trades memory for fewer spills on large documents; lowering it caps the footprint of a server process that saves many documents at once. A value of 0 makes every save spill immediately
A negative value or one above the supported in-memory range raises EPdfError. Where the spill files land is controlled by SaveTemporaryDirectory, and what actually happened is reported by LastSaveSpillCount and LastSaveLargestMemoryBuffer