MemoryCacheSize controls the number of compiled files (.pyc and .pty) that PSE keeps cached in memory.

Usually a page has two of these files, one for the template and one for the python code. So if you wanted to keep 50 pages cached in memory for maximum performance, you'd want to set MemoryCacheSize to 100.

Setting MemoryCacheSize to 0 means that no compiled files will be cached in memory and that the file system will be consulted for each page access.