Paul White NZ (3/31/2010)
Assuming the box is licenced per-processor, would you expect any advantage to running the separate distribution databases in separate instances?
I'm not up to date with licensing requirements on multi-instance installations.
Having multiple instances running on one box strikes me as a good way to detract from the available memory so anything you would gain from instance isolation is lost to the memory requirements of separate instances.
This is outside of my area of expertise.