My zope clients (Zope2-2.12.11) allways start with 5 theads although zserver-threads is 2 in my zope.conf file.

If for zserver-threads I use the values 1, 2 or 3 I get 5 theads.

A higher value give me 2 threads more. I mean, for 4 I get 6, for 15, 17 threads, etc.

It's correct? There are allways 5 threads minumun and 2 extra?

It's a plone site. I am using zeo with separated catalog. I have 16 instances in a 8 cores machines and I think the GIL is making a poor performance. 

Thanks