Just to throw in my experience...
I never once had a time issue on QBank, always finishing with 8-10 minutes or more on 50-question blocks. And I treated QBank as a true testing experience each time, not just guessing or flipping through questions when I didn't really know them.
To my surprise, when I took Step 1, I came down to the last minute on every single block, and I don't really know why. The questions didn't seem longer, although they seemed much different in scope and concept than QBank (I can't really describe it better than that). I guess I did spend more time than usual reasoning things out on the dry-erase boards. I also took more a few close-your-eyes-pray-and-take-a-deep-breath breaks within the blocks to alleviate the anxiety associated with long sequences of totally unexpected questions 🙁
A couple friends who took the boards before me related a similar experience, so long story short, be prepared for a little more time pressure on the real exam.