I've been running a bit low on memory recently, so I decided to find out where it's going. Obviously my browser is pretty memory-intensive, but I'm not sure there's much I can do about that (short of browsing less, all I can do is tune settings and/or change browsers). So I opened the system monitor and closed out the biggest memory users: firefox, soffice.bin, evolution*, and evince (I had a decent-sized PDF open). After closing those the memory use came down a bit: the largest memory users remaining were nautilus and gedit at 16 and 10 MB, respectively; everything else was taking a very small amount of RAM.

But the total memory use was still above 800 MiB: I calculated 810-812 MB not accounted for in the system monitor. The system monitor helpfully reported: "51% in use from programs, 11% for the cache" or something similar. Why is memory use so high? Vista only requires 512 MB; I have trouble believing that Ubuntu is greedier.

So I guess my questions come down to:
1. What is using the remaining 800 MB?
2. How can I reasonably conserve memory?
3. How long before someone tells me to buy another 2GB?

* Why was evolution running in the first place? I don't use it and I've never opened it.