We already know that's not at boot up. That's after you've been up and running for awhile.
Someone else's RAM usage is going to have no bearing on yours. The apps they use will be different than yours and how much each of those will store in memory for fast access when you open them back up will be different.
Whether the CPU is sitting at idle has no bearing on the amount of RAM that has been used. Mine is currently at 97% idle and have 1.95GB of RAM used. My machine also has not been shut down in maybe a week.
Also, the more RAM that you have installed, the more RAM that your machine will utilise.... Sounds strange I know, but you need to take into account how it will use the RAM if you have ample available.
For instance, during the same tasks, under the same conditions, my i5 MBP with 4GB RAM used less RAM than it did when I had 8GB installed, however, it is more so about how it used the RAM that was available.
I found a really good article a while back but can't find it now.
I have been having beach ball"s and freezing issues the mac genius thought the ram usage was a little high and causing these problems he told me to monitor it and he wiped and reinstalled the os due to that but I'm still having problems it's upsetting as i have heard such good things about mac (this is my first) but at this point I can't agree seems was overpriced for a machine that is crashing all the time thats why I replace my 6 yo hp
Make an appointment an have them look at it again.
If they see there is a problem and can't fix it, after 3 attempts at the same problem, talk to the manager about getting a replacement unit.
Otherwise, call customer care.
Do all this with a pleasant demeanour and no chip on your shoulder.
Mind you, if you are getting beach balling and freezing while doing certain tasks, you should be able to emulate that when you are at the genius bar.
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