Many BackgroundJobServers in one process - Performance problem

question
1

I run 30 BackgroundJobServers in one WindowsService(one process). Each BackgroundJobServer has 10 workers.
That configuration works very slow.

But in case when I run 30 BackgroundJobServers in 5 WindowsService(5 processes) - 6 BackgroundJobServers for each one process it works much more faster.

First configuration is wanted by me.
Any tip?