Oh happy day, the last update caused a very strange problem on multi-core machine. This has been fixed! :)
Sometimes the game would pause for a second or two, and there were hellish stutters and performance issues.
On my single-core laptop these problem did not exist so i had to install a 3rd development environment on a multicore machine to test/fix it.
The problem was traced to a piece of optimization code that did not work as expected anymore.