One other thing, I'm not actually completely convinced there isn't a memory leak going on. Even taking the cache/buffer into account, memory usage is way above what it seems it should be.
For example, you're showing about 110MB of memory in use. Running rather few programs, I was showing about 140MB (cache taken into account). Anyway, I guess I'll have to do a more in-depth analysis to be certain. I suppose I'll do that later.