1/2 sim, but only 1800 prims, how is this possible??

Where would you go look for the total amount of prims available simwide? You can tell how many prims are rezzed on the sim, but that doesn't tell you how many are there total. The only way would be "# prims on parcel / m² / bonus factor * 65,536m²" which implies knowing and spotting the bonus factor in the first place in which case you could just tell from the bonus factor and prim count alone.

If one of the four parcels in the previous example has 3750 prims on it then the other three will still show "0 out of 3750 (3750 available)" because the parcels have different owners.

"Simulator primitive usage" will top out at either 3750 or 15000 but it doesn't relate to the sim, it relates to multiple parcels with the same owner across the sim which is why you'd have all 4 owned by different alts.

Ok, I"ve been living on my own sims too long.

As an Estate Owner, it lists total sim prims too. I didn't realize that doesn't show for everyone. I think it should, and there's really no reason I can think of it shouldn't.

It's around somewhere, I've read it regarding open spaces running 16 to a server on quad cores.

Nope. Class 4 and class 5 servers both are twin, dual-core systems; two physcial processors, each with two cores.

Four cores total, per server. One openspace sim takes 1/4th of a core. Sixteen openspace sims per server.

I think this has changed Sindy:

"An Openspace is a type of private island intended for light use countryside or ocean. Unlike normal regions that effectively get a CPU to themselves on the server, there can be up to four Openspaces on a single CPU, sharing the resource (hence them being ‘light use’)."

http://blog.secondlife.com/2008/03/07/announcing-changes-to-the-openspace-product/

I'll bet any reasonable amount you want that they mean CPU core, not CPU...

Surely you jest? That's incredibly bizarre that they want to be the next big thing and run on dinky hardware like that...does anyone know if they are upgrading?

http://blog.secondlife.com/2008/02/13/there-is-no-class-6/

The requirements for a 'good' desktop are far different than those for a 'good' server. The sims servers don't even have what you'd call real graphics hardware in them - they just don't need it. (this, btw, is one reason LL is so slow to update the map - the sims have to calculate the map image in software, which is way more painful than asking a vid card to do it.)

Not by any means saying that this is state-of-the-art hardware, just that it's not necessarily as bad as it sounds.

Naughty Sindy, gambling is banned

I can't find where I thought I read that they were using quad cores for openspaces, I can find where I made a comment in blog comments that I couldn't find anywhere that had stated they were now using quad cores though!

Whatever the actual tech and terminology, it remains that they are running four Opensims with the resources normally used to run a normal sim.

Getting back to the thrust of the OP:
An Opensim is a resource-challenged sim.
It is possible that people are buying/leasing Opensim parcels without being aware that this is so.

I know that the Linden water sims in the Korean Channel are Opensims. Performance varies erratically even with a single avatar (moi) in a sim populated by a few plants.
These are NOT sims in which to expect good performance when they are loaded.
Whether they are hostage to the loading of three other Opensims only or to the loading of the fifteen other Opensims in the same server seems unclear.

Games of chance are!

This is where the blog about land expansion annoyed me. They again pushed their product, and why shouldn't they, it's a money maker. However they made no mention of the intended use or the usage they will support on these Openspaces. They know damn well people aren't buying or using them for "Light use", so either support them properly and change the blurb or be honest about their use.

sounds like a void sim if it is 18oo prims..
they upped voids to 3600 prims
half that is 1800