Sybase ASE CPU very high while OS CPU is low. (4287071)

We are currently experiencing an issue in our Sybase environment. When we use Spotlight on Sybase 2.0.0.581 to help diagnose the problem, we find that the ASE CPU numbers are very high while the OS CPU numbers are low.

In the past these two metrics have always been the inverse. This we can understand because we have 15 Sybase engines running and when there isn't enough work to keep them all busy, they burn up OS CPU time looking for work. This is described in the Sybase manuals.

Can you give us an explanation of a situation that would cause the high Sybase but low OS CPU utilization?  

We'd  like to know what circumstances would cause Spotlight to show a high number of "active" users (70-90) when Sybase Central at the same time only shows that a dozen or so connections are running SQL commands.

The other thing we can't explain is how the ASE CPU can be so much higher than the total CPU on the server. The only thing running on our server is this Sybase instance.