MaxCase's Sim Neighbours was a very enlightening database, and when it went belly-up it was missed. There's a new database, though, which is interesting to query as the Lindens now put eight sims to a server, supposedly.
Find That Laggy Second Life Neighbor!
Argent Stonecutter explains it clearly: "Most sims don't actually need 800MB working set. On average a sim will be N megabytes below 800MB working set. If you have 4 sims, on the average someone would have to be 3N megabytes over the limit before you start paging. If you have 8 sims, they'll have to be 7N megabytes over the limit before you start paging.
Another way to look at it, with 7 sims on the server, the odds that you'll have an unusually "fat" sim go up, but the odds that you'll have one or more unusually "thin" sims go up as well.
Another way to look at it, if somehow they were putting ALL the sims on one server with I don't know how many terabytes of RAM, the impact of the "fat" sims would be so diluted you'd never notice.
This is basic queueing theory. It's why timesharing services and any other service that has large scale sharing of resources allow overcommitment. It's why sharing a motorcycle with a fat guy is so much worse than sharing a 747 with 30 fat guys. The more resources are shared, the less impact any given freeloader has."
posted by - 7:00 PM