Hi Shelli. I'm a zone 3 and have raised beds with perennials in them. Specifically a Autumn Joy in my raised bed for years, along with my more delicate roses, etc. I haven't had any issues with them not holding over winter just fine.

Containers are smaller and freeze differently than raised beds. I don't leave them in containers. .

Shelli, I'm in a cold zone also and I had asked a while back in the container forum about perennials being hardy in containers since I live in an apartment and have no real garden space.
The info I got was that if the containers are open on the bottom to the soil below, they have a good chance of surviving, otherwise there is not enough of an insulating barrier from freezing temps.
If your perennials are hardy to your zone, they should be fine in a raised bed since the roots have access to deeper soil below and better protection from the cold.
I actually had some chives and thyme survive sub-zero temps last winter that were in large(and very thick)cinder blocks. The holes were open to the ground and the blocks were next to the building, then with a good covering of snow they made it through almost 30 below temps. I was very surprised(but happy).