I had random lockups/freezes with Deus Ex: HR as well with my factory overclocked MSI GTX 570 under DX11. Bear in mind, I've had ZERO issues with any of my other games I had been playing (Civ V, Portal 2, Mass Effect 1/2, GTA IV, Bioshock 2, etc.)
A quick search on Google
will generate plenty of hits with people encountering similar issues. You'll find more of the same in the Official Eidos Deus Ex: HR forums.
Also, both nVidia and AMD users are encountering the issues.
Solutions varied from setting overclocked cards to factory speeds, adjusting GPU voltage, adjusting CPU overclocks and voltages, running in DX9 (and taking an image quality and performance hit), drivers, etc.
For me, I ended up running my GTX 570 at stock speeds and upped my CPU vcore slightly (I am overclocked) and was able to (thankfully) finish the game without further incident after applying those changes.
Further to that, there had been firmware updates for various nVidia cards that did adjust default voltages.