OK, I know this must have been answered satifactorily somewhere, but i've looked around here and googled it and I just can't find a good thorough answer to what "WIPE CACHE PARTITION" do.

I know what cache is, but what is this caching? and whay is it a seperate option from a factory reset? I would think resetting to factory would wipe anything cahced form the user, unless its not just user data....

I've been having lag issues with my phone on 2.1 and 2.2 and i'm going to reload the stock 2.2 again. But I wonder if wiping the cache will be benificial also?

Does anyone know exactly what this does? Thanks!