Comment by foldr

Most of the empirical comparisons I've seen of the 8GB vs. 16GB models show that you have to push the 8GB models pretty hard before they're noticeably slower. Most of the complaints seem to come from people who are obsessively checking memory usage and have a rather over-simplistic mental model of how RAM is allocated in a modern operating system. (For example, many apps, such as browsers, will happily use more RAM if you give them more RAM.)