I’ve noticed that APC and other opcode caches can help with memory, since retrieving the opcodes from the cache require less memory than parsing the PHP file each time. The first time a PHP file is parsed, the scripts memory consumption will be high, but subsequent calls are smaller.
Depending on how memory starved your server is, this can help some as it keeps the memory usage for apache lower, especially if you use prefork.
Do you have any benchmarks for how much turning stat() off can help?
