Be very wary of fake Sandisk cards, both Secure Digital And Compact Flash. They are everywhere. I have over 300GB in CF cards and have been caught out once. The 8GB card was a very good fake, but the read/write times where very slow and was very unstable.
Always best to pay an extra couple of quid and get the real deal. Although I once ordered two 8gb cards from
7dayshop for a good price.