I do happen to have an 8 GB machine, and almost never reboot (only reboot for OS updates).
I run half a menu-bar full of resident helper apps, like Dropbox (a big one), Fantastical, ScanSnap, Xmarks (another big one), Transmit (another big one), Evernote, and more. I also keep Apple Mail running, mapped to a half dozen Gmail IMAP accounts. I have "geek tool" updating my desktop with iCal appointments and various ps outputs.
I'm running a local MAMP stack and local Django stack. I run a Parallels Windows 7 VM for testing things in IE and testing from Windows in general.
Other running software is usually Safari, Terminal, Sublime Text 2, Codebox, Source Tree, Sequel Pro, Adium. I run and quit Office 2011 every time I need to edit a document. I run and quit Aperture and Photoshop.
Using this command line to see memory used by processes:
I do happen to have an 8 GB machine, and almost never reboot (only reboot for OS updates).
Here's what I don't understand - why would anyone in their right mind purchase a $2000 laptop and then not spend the 20 minutes and 100 bucks to max out the memory on the thing? It's the easiest thing in the world to do, and basically means you never have to worry about memory usage again.
Recall that what "matters" is really that second line, which translates to 740MB being really "used" and 3.1GB being just "stuff I happened to read from disk at one point", which as it happens includes rather a lot of media files. Loading another 4GB of media into RAM isn't going to help my system performance any.
This is with a respectable Linux dev loadout, but I'm not running my VMs, but that still tends not to strain my system any. $100 on RAM would just be a wasted $100.
And-or get an SSD - the heavyweight disk-space users like movies and music are trivial to move to an external drive on a Mac, and with an SSD so much disk-thrashing pain just goes away. It's pretty great.
After noting my rather older MBP with 8GB RAM was outperforming my new iMac, I spent $16 for 4GB of RAM (doubling the total to 8GB); the iMac's performance improved immeasurably. By far the best bang for the buck on OSX is maxing out the RAM. (Well, at least until I can afford a solid state drive of adequate size.)
You add the individual RSS of every process, but processes share physical pages, so that doesn't make any sense. You're counting physical pages more than once. For example on my 4GB laptop you're command yields 5.6GB, and I don't even have a swap partition.
I'm skeptical about your little script (though I too have a lot of heavy apps open all the time and almost never reboot, and certainly have never, ever had any memory-related problems whatsoever).
My MBP has 8 GBs of RAM, and this is what Activity Monitor tells me:
I run half a menu-bar full of resident helper apps, like Dropbox (a big one), Fantastical, ScanSnap, Xmarks (another big one), Transmit (another big one), Evernote, and more. I also keep Apple Mail running, mapped to a half dozen Gmail IMAP accounts. I have "geek tool" updating my desktop with iCal appointments and various ps outputs.
I'm running a local MAMP stack and local Django stack. I run a Parallels Windows 7 VM for testing things in IE and testing from Windows in general.
Other running software is usually Safari, Terminal, Sublime Text 2, Codebox, Source Tree, Sequel Pro, Adium. I run and quit Office 2011 every time I need to edit a document. I run and quit Aperture and Photoshop.
Using this command line to see memory used by processes:
Gives 3000.535 MB for all of the above, 3235.000 MB after adding Word and Excel, or 3794.277 MB after adding Photoshop CS5 and iTunes streaming radio.Makes me wonder what you're doing to run out of memory.