The difference from 1024 to 817 is system used, so the balance is used for everything else, apps etc.
What I would like to know is if anyone else see's what I do and tell me why different free ram readings? Pull down status bar and hit quick settings tab. Right now it shows total memory 817mb, used 691mb, and 126mb free. Then go into settings open applications and hit the running apps and at the bottom left it says 228mb ram used and right lower corner it says 545mb ram free.