Hi Toby I always thought that the object cache was per thread! If you're right then you are exactely correct and I have to up the cache accordingly. This exact Test is running at the moment so I'm curious what the results will be ;-) Zope 2.6.x ist still way off on my hosts ;-) Since you're using -t 2 on your Zopes are you also using ZEO? Oliver Erlewein