I know from experience on all of my macs that apple's official ram limits and actual limits are two totally different things. What is the actual maximum ram capacity of this machine? is there a firmware block, or is just limited by the maximum GB of the total of 2 sticks at that bus speed. I know that you can now get single 4GB sticks, so in theory, one could put in 8GB, but that would all depend on a firmware block from Apple. On my late 2008 Macbook Pro, It was initially limited to 4GB, then a firmware update was released for a certain lot of serial numbers that supposedly increased the limit to 6GB, however, I've had 8GB from the start.