Chrome parent mem useage - why is it incorrect (applies to any program too)

I am used to many of the stats displayed by task manager or process explorer. I don't implicitly understand them all, but I have a general knowledge of what they represent.

I wonder if anyone has infos on why Chrome in particular has the parent process that shows for example 37,000 k useage, (private, with 61,000k working set) but if you examine each child process, they total much more than either the private or working set. I always assumed it was that each child process had included in its stats some base code that was present in each, but likely to a shared memory source. I have never seen any documentation on this, and really don't know what terms to use to find proper results.

The same could go for any program, but it has been typical for me see the parent total being a cumulative of the children.

I bring this up because I have been playing with the cache Chrome, and realizing Chrome is not as fast with a small cache (for me anyway) and examining other browsers cache and performance got me looking again at different browsers again (sigh). I have been testing Avant,Maxthon3,IE,FF,KM,Chrome,QTweb and Opera. Nothing ground breaking, just examining each in terms of disk space used, I/Os, cache sizes - all relating to performance and footprint. I don't really have an urge to switch, just learning.

Anyone have infos to share?

Sul.