You might expect the SHM functions to be significantly faster than building variables from MySQL operations. Unfortunately this is not the case regarding large multidimensional arrays. I've tested write, read, update and delete operations with with a two dimensional associative array directly with SHM and in comparison with a class using MySQL and a class using SHMOP functions (with mostly offset-accurate serialization). Both classes generated the same array as stored with SHM. Unlike SHMOP the performance of SHM decreases considerably with larger arrays. At 2000 instructions with an $array[$row][$key] of 200 rows and 5 keys even MySql is faster than SHM.This might be due to the fact, that SHM deals with any kind of arrays and makes internal use the PHPs powerful serialize() function.