Been having a weird issue with my MBP lately... it came stock with 2x2GB DDR3 RAM. A few months ago, I upgraded it to 6GB of RAM (1x 4GB, 1x 2GB), and later to 8GB (2x 4GB). Everything worked perfectly, other than when I first started it up after adding the 8GB (wouldn't start; re-seated RAM and all was fine). Once I acquired my mini (bought it used), after about a month I moved the 8GB of RAM to it and the 4GB of RAM it had to the MBP. The mini's RAM was known good; I had used it for at least a month with no issues, and the previous owned had never had problems with it, and the 4GB worked fine in the MBP for a while (a month or so at least). The 8GB works fine in the mini, too. However, my MBP now has "issues" - occasionally it will freeze for no reason at all and/or on start-up, well it won't - all I get is the boop-boop-boop bad RAM beep. What I've tried: The 4GB from the mini was known good, but I've tried switching them back, I've tried other RAM from other upgrades that I had on hand that were known good, etc. I think I MAY have found the problem, but wanted to seek advice; it appears that the lower memory slot is bad. I can install anything in the upper (close to the keyboard) one and it works every time. If I put a stick in the lower slot, it's hit or miss. Last time I tried this, I tried every 2GB stick I had (4 in total) in the lower slot and it wouldn't boot with ANY of those installed, but if I put any of those in the upper slot, it worked perfectly. Any ideas? Or is it dying a slow death and I need to just avoid the flaky slot?