Wanna use lots of RAM? Get a 3d modeling program and make a crazy high poly scene, a fluid simulation, or a 1,000,000 particle effect. That'll use up your RAM
. Also, have Crysis open at the same time
. Also, if you have all of your RAM used, it makes your computer feel really laggy. When I'm baking a fluid simulation at high resolution, my computer isn't usable, and that's no fun. Just be happy that your comp doesn't use all that RAM.