[Pharo-project] Strange slowness with PharoBoids

Hi I took the image of athens mentioned by camillo a while ago and loaded PharoBoids. It was fast with 20. I played with the system I played with the athens playground and saved. Now I wanted to do a demo and it was getting slow. I killed a lot of process using the process browser but it was still a bit slow. Does anybody experience the same? I will try with the latest version of athens. Stef