Pathogen#1
The Orange Box games are primarily CPU-bound, and it's all about speed (ghz). You'd think a GTX 670 should have no trouble running it, but a faster CPU will see more benefit than a better GPU. I have an i5 OC'd to 4.3ghz and the game runs pretty great, for the most part (attacking top left of Badwater out of BLU primary spawn has never not felt like my game was about to die, for example). What's your i7 clocked at?
If you've never overclocked I can point you at a decent guide or 2.
I have an i7-3770K which is pretty much the best non-haswell i7 out there. I really cant believe this wouldn't beast tf2 out of the box.
I have never OC'd but I reckon my cpu is one of the best to do it, I would definitely be interested if you could point me some good guides, although I have heard its risky before, but last time I tried something similar was like 6 years ago, so Im really not on par with that kind of stuff.
PathogenWith regards to your GPU: I find a high (capped 132), relatively stable framerate to be a much better experience than a very high (350+), wildly fluctuating framerate. To that end, I bumped up my AA and Filtering recently, both of which are GPU intensive tasks, and my game felt smoother (which is the most important issue here), as well as looking better. The overall framerate was slightly lower, but there was a definite drop in how much the framerate was varying. Note: This is for a 60hz monitor. I've never used 120hz, so I can't speak to that, but I do notice fps drops from 132 to 80 (12v12 mid-fights), but there's usually some network choke to factor into that scenario too.
I know its much better to play with a smooth fps even if its a bit lower, which is precisely why I have been noticing huge differences, because its not so much the fps difference but the huge constant drops and flutuations that previously didn't happen. Even if I had 140 fps I had them slightly constant where as at the moment Im flutuating like crazy between 120-70 and it really messes my game up.