First off, I know it's not faulty RAM because I have a Windows partition on this drive and Windows is perfectly fine. It's only when I use Lion that the mid 2009 macbook pro acts up. Random hangs that don't seem to be related to anything, black screens forcing me to hard restart the laptop pop up almost every time I watch a youtube video or whenever they feel like it. I can't take using Lion anymore because I never know when a crash is going to be right around the corner. It's a fresh install of Lion and the only app I generally have running is Radium and Chrome, so I'm no where close to taxing the system and I had more programs open and running and working fine with the stock 4GB without any problems. Hopefully I can get some input from you guys!