[calloc]

Remember that when you are accounting for those you also need to remove all of the stuff that is paged into every process and is the same across them, such as shared libraries and the like. Most likely Chrome is using less ram than you think.

[makomk]

Chrome has a built-in task manager that takes this into account, as well as a slightly more hidden "Stats for nerds" link in the task manager that gives total memory usage. It's just genuinely very memory hungry once you add up all its processes.