The QA on this game was clearly not strong.... Anyway, these fixes solved 100% of my performance issues. There are different registry fixes floating around but they did not fully fix the problem in my case.

FIRST FIX

Taken from Steam forums and Guru3d forums.

In regedit open:

HKEY_CURRENT_USER\Software\Eidos\Deus Ex: HRDC and locate AllowJobStealing - set it to 0

For NVIDIA owners - in HKEY_CURRENT_USER\Software\Eidos\Deus Ex: HRDC\Graphics locate AtiForceFetch4 - set it to 0

SECOND FIX (For Nvidia SLI users only)

The game flat out does not possess an SLI profile (at the time of posting this), but you can use the one for the original Deus Ex: Human Revolution without anything catching fire too dramatically. Just find the original Deus Ex SLI profile in whatever SLI profile manager you use and add the Directors Cut executable to it.

It's weird how this happened again for the game. This was a problem with the original release (same fix as well) that was patched out within the first week or so. The fact that this issue popped up again makes me wonder if the directors cut was worked on an unpatched version of the game. Also, since the original version of the game was fixed, this makes me wonder how long it is going to take to get a new patch out for the directors cut.

Directors Cut is the first version of the vanilla game, im guessing theyll patch it again at some point.