High Memory Usage on Clients

Hi,
I have a WordPress site up with only 6-7 posts so far. I was working on a custom theme when I noticed that it was really laggy. I checked in Chrome’s task manager and the home page was taking up a minimum of ~200,000 Kb of memory. I switched back to the Twenty-Twelve theme and it still takes up ~100, 000 Kb idle, and up to ~600, 000 Kb while scrolling. This is not normal, is it? I mean Facebook with dozens of posts only takes up 50, 000 Kb. I also checked in Firefox on a Linux computer, and it was also taking up a great deal of RAM.
Any help would be great, because the site is practically unusable.