Why? Unused RAM is just wasted RAM. In an ideal world, we would use all unused RAM for aggressive caching, and release it just before it's needed by something o

Why? Unused RAM is just wasted RAM. In an ideal world, we would use all unused RAM for aggressive caching, and release it just before it's needed by something other than caching. That Firefox frees up the memory when you start other apps seems to indicate it does it exactly right.