etherHKetherDo you havea 7xxx series gpu?
Nope. 6670. I've noticed the same thing though, and it isn't easily reproducible.
I was going to buy a 120hz monitor but after seeing a lot of people complain of it not feeling like 120hz, I'm really hesitant.
I've got a 7850 and I've not had this problem at all, I'm even running two monitors off of it (One at 144hz) and my fps in tf2 and other games is fine. The only times I get micro stutter is when steam dies and it signs me out and back in or w/e it does.
Edit: When I had one monitor running off of my gpu and one off of the onboard graphics any animations on the on board would destroy my fps. On board was the 60hz monitor the gpu was 144, you didn't say if you have one or two monitors but if you do I'd check that.