I really don't know how to reproduce it. But every so often I'll notice my new Alu Macbook make a quiet little Whrrr noise. It almost sounds like the optical drive wants to start up - but the sound only lasts for like 1 second. Like I said, it's pretty quiet. But strangely, sometimes it will happen repeatedly. For example, the first time it happened, I heard this little whrrr, and at first I wondered if I left a disc in the drive. As I was pondering that, it happened again. So I lifted the macbook up to listen closer. Every 10 seconds or so, for the next little while, I heard it again. But for the life of me, I couldn't figure out what it was. After a few times, it stopped happening. Since then, it's happened a couple times. But honestly, it's so quiet, that if the tv is on or something, I probably just wouldn't notice. I haven't had another chance like the first time, to hear it back to back a few times. Like I said, it's a pretty quiet sound. It sounds a little like it's coming from the optical drive, but I can't say for sure. Could it be the CPU fan starting up? If so, why would it happen periodically? I also wondered if due to me moving the laptop around, could it be "parking" the hard drive? I doubt that though because the hard drive is on the opposite corner of the laptop (not where the sound seemed to come from), and it's not like I was shaking it around or anything. Has anyone had a similar experience? My old macbook of 2 years never did this. I did order my Alu MB the day they were announced. Could this be one of those "kinks" that they need to iron out?