When creating a quiz, I can only see the first 10 items listed that have been added. This is 2.1+ install. I have developer debug set and get no messages. The script isn't taking that long so I don't think it's timing out. I don't know about how much memory the new engine might use, but I'd be suprised if it's that much.
I can see an arrow from the 11th item and can move it up so that it becomes the 10th and see it, but ...
I can't rule out that I did something strange in the settings as we just upgraded from 1.9+ back in June.