So I've had a 4GB OWC kit in my unibody for a few weeks now and things have mostly been OK. There are, however, occasionally minor glitches that arise, the most annoying of which is the following: I have movies stored on an external HD connected via USB. Occasionally, I will play a movie in VLC and playback will just halt. If I close VLC and try to open the file again, the movie will not play at all. I will try to open the file with Quicktime, which then tells me I do not have sufficient privileges to do so. When trying to browse the disk in Finder, files will then appear to be missing. I know it sounds like an HD issue. I've run Apple's hardware test from my boot CD and am trying to get my hands on a copy of DiskWarrior to see if anything is up. The drive is fairly new: a WD 500GB GreenPower drive I purchased earlier this summer to be used for media storage and Time Machine. I just wanted to see if this could possibly be one of those RAM issues that hasn't been corrected and see what utilities people are using for memory testing.