On my Razr, with a whole bunch of tasks running in the background (including Google Music, the phandroid App, Tasker, a few widgets, and Touchdown), I have 347mb of RAM in use. My old Droid X with almost nothing active anymore (since it presently has no network access) is running at around 230mb of RAM in use.
Considering how much more I'm asking my Razr to do at the moment I don't see that increase in memory as significant...
Almost 700mb of RAM in use initially on the Rezound? Hmm... either someone installed something that really chews up memory or there has gotta be something not kosher with that particular handset!