I'll check again tonight, but I for sure have never breached 4GB of RAM used. My highest 5 group is 65 so I've yet to 5 box in Dalaran, but still...during the Fire Festival there was a good amount of activity in some other capital cities/Shat.

I really think keeping the graphics settings low on the 4 clients is key, if they don't have to render gobs of data for things too far away to matter to a child instance of WoW, it must help with things.

But yeah, I'll maybe summon myself out to Dalaran soon and see how much mem usage I have like this.