Post: #2

UO, not sphere, is limited to about 4 billions of entities (items+chars+any other server needs)
The most crowded server I've ever found contained about 100 millions of items and not 200 thousand of chars, not even close to the UO limit

The performance depends on what hardware you're operating and what active systems and player base you have. Performing world cleaning may result in better performance, but performance may be getting hit by many factors than heavy amount of items

We can't tell you how to fine tune as they may vary to fit your needs, out best is to give you tips that can help solve performance problems

Performance problems should not be noticeable on a running server, only during save only if you have a large amount of items.
If you're noticing performance slowdowns during gameplay, you will have to check your system and if that not solve, check your scripts, one ore more of them may be consuming too much resources