I have a 15" Late-2011 MacBook Pro with an AMD Radeon 6770M Video Card. I purchased this from Apple in November 2011 with an AppleCare Warranty. I've read through countless threads about the faulty hardware components and Apple's Repair Extension Program for Video Issues, however I've yet to have any problem with my laptop since day one. I want to make sure my laptop remains good to go before Apple's repair program ends. How can I test my laptop's video card and put it through some stress tests to determine if my machine is faulty? Thanks in advance.