Phone very slow to respond

[witNer]

I've been searching through the forums to find if my problem is the same as others. When running applications which are installed on my memory card they seem to be very, very slow and almost come to a complete freeze. I'm not sure if this is the memory card (bought from Ebay) or a general performance problem of the phone.

I have the O2 version with the original rom installed.

Is it the phone or memory card?