Hi guys, I just got my 2.53 ghz core i5 MBP today. As soon as I turned it on it said the battery life was only 4.5 hours. I'm kind of worried because Apple advertises 8-9 hours. Bluetooth is off, wifi is on, brightness is up about 3/4 of total. What is going on??? What were your battery lives like when you first got your i5 or i7?