Edimax EW-7711UTN 11n 150mbps adapter

I have a BT Home Hub 2.0. This Edimax mini adapter was highly recommended on the BT website and also got good reviews on Amazon where I bought it from. I bought two of these for computers running XP. The adapter is tiny but also comes with a small extension which acts as an aerial and is supposed to help with poor connections. The computer furthest away connected but only ran at 6mbps - I put the Linksys wireless g adapter back on and got a consistent 54mbps. The other computer is almost directly above the router and it connected to the router at 65mbps but could not access the internet no matter what I did. Again I reinstalled the old Linksys adapter and got a consistent 54mbps. I am running the HomeHub on the recommended b/g/n setting now. I returned both adapters to Amazon for a refund.