To add (or clarify) to this, it seems like the Auto-Detect function just doesn't properly scale back settings based on hardware. I have tried 3 different hardware configurations (two CPUs and 3 Video Cards) and each of them Auto-Detected to ULTRA.
It's most likely that the auto-detect feature just isn't working as intended right now.
Overall not an immensely helpful post for other forum goers- so next time try to provide a little more info on what kind of hardware you're using (specifics are 1000x better than "new card") or something of functional value to the other testers or at least the developers.
Best of luck playing it on low-med settings. I had a lot of trouble when using a lower-end build running on Medium settings at 720p. It's Early Access after all- the better the quality of your feedback, the better the improvement.
Cheers.