Annoying Framerate Issue

[Bitch Puddin']

I recently picked up Deus Ex: Human Revolution as part of a steam sale, and I'm having an annoying framerate problem which invariably occurs everytime I strafe and simultaneously move my camera (mouse/ cursor/ reticule) along the X axis. When I do this, my framerate goes from a solid 60FPS down to somewhere below 20. I have no issues with screen tearing or other graphics issues.
I have a brand new alienware PC which runs Far Cry 3 at the same resolution on which I am running Deus Ex with ease, thus, I am wondering why this issue is occurring, and whether or not I can fix it. Any help would be much appreciated.

[VenomBlade]

Hey bud, give this a go. I know it's more meant for people experiencing stuttering in this game, rather than large frame dips, but it can't hurt

http://www.youtube.com/watch?v=ih9ztmBFYDw

[Bitch Puddin']

Thanks, this helped a lot.