Extendir is a file system filter driver that significantly increases the performance of your phone, in specific situations even up to 12 times as fast and faster.

Changes:

Removed settings through registry, this was added in v1.01 but that gave major freezes and lockups with some devices. Well now is everything stable, no more freezes and no more lockups!
Released different versions with different cache settings.

http://forum.xda-developers.com/showthread.php?t=530710