A few weeks ago I bought a brand new mid 2015 15" Macbook pro. The high end version with the amd card. It came with a dent on the back. It was almost unnoticeable and one could say it was more cosmetic than anything else. I used the laptop for a few days and I was a bit surprised with the performance. I thought the laptop was gonna be much faster (my previous laptop was a 2013 macbook pro). Also, I was getting at most 3 or 4 hours of battery though that could have been due to me using firefox instead of safari and having the screen at 100% brightness. But even worse, was firefox performance. The performance was fine in the first couple of hours of use every day, but after a few hours, usually around night time, it would always get incredibly laggy and buggy. While using firefox, I could not go more than 20 seconds without getting the spinning beach ball of death. Ultimately, I decided to return the computer due to all these issues though I spoke only of the dent as my reason when speaking to Apple. They sent me another Macbook pro. Believe or not it came with the exact same dent on the exact same place. I am 99 % sure it's not the same laptop though However the battery is behaving the exact same way. And so is Firefox. And I'm left wondering what the hell is going on. As I'm writing this message, I can't write more than 5 words without getting the spinning beach ball. Should I return this macbook pro as well? Is slowish and laggish performance on firefox a common issue among mid 2015 macbook pros? Help me please.