I just recently got a 15" Unibody MBP, 2.4 Ghz base unit. I want to upgrade the RAM to 4 Gb. I went to OWC, I've had good luck with their memory, but they're showing an upgrade to 6 Gb in addition to the 4 Gb. Will a 15 " Unibody accept 6 Gb? Will it be able to use it? Is it of any use if not running 64 bit apps?