The reason why Algorithm::Diff is slow, is because is has a totally different purpose (but can be used to do what you need). Algorithm::Diff is an implementation of UNIX's diff, which basically shows you the difference between files. Diff is used with patch when bugs are found/fixed.

Anyway, more information is available on the Algorithm::Diff POD, Dominus has a page on it, and ofcourse, you can check the diff manpages

Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.