I'm fairly new to Mac from Windows and am trying to figure out what the numbers in the Activity Monitor mean, so I can manage memory a bit better when the computer slows down (MacBook 2 GB RAM). I read elsewhere that the number of page outs should be below a few thousand per day and I see page outs as a dimensionless number in all the screenshots I've seen, but in my Activity Monitor it appears in MB. How do I interpret that?