So I thought I'd share a story that is more about my own mistake than anything else, though it might help some of you depending on your display:
Most of us are aware of the input lag our TV's, monitors, and Projectors have (separate from network lag which is a whole other deal). For twitch games like COD bad input lag can really be a problem no matter what device you play with. However, for the past few years, as manufactures have wised up and gaming studios have learned to compensate it hasn't been much of an issue - modern LCD TVs and Plasma's generally have lag in the sub 20ms range, which for most console games (and most gamers) isn't noticeable.
However, crappier TV's, as well as even good projectors, do still have the problem, and for that matter even "good" TV's often have special modes for gaming - particularly TV's that offer post-processing like Frame Interpolation (it's known as the "Soap Opera Effect" where even movies look like they were filmed by a video camera. Some viewers actually like it - it makes things look "real" but it adds a LOT of input lag with games).
I myself use a PJ, the Epson 5030UB, which is an awesome quality PJ and means I can game on a 120 inch (10 foot) screen, which is something else let me tell you.
However I completely forgot that the PJ has a "fine/fast" setting which is what other manufacturers sometimes call "gaming" mode. "Fast" processing means a little less image quality (which in a game you wouldn't notice, only a movie, and even then only if you have a giant screen and are picky) but 25-30ms response time, which isn't top notch but unoticiable by all but the pickiest tournament-level twitch gamers.
"Fine" mode boosts input lag to over 100ms, which most anyone would notice.
Guess which mode I've had my PJ in by accident the past two weeks

I've been going nuts with my XIM4e, adjusting configs, tuning, tweaking, switching peripherals - nothing. The games "felt" ok but slightly "off" and more to the point I couldn't seem to hit much of anything, even if my sights looked dead on target. I'd go 5-30 in COD:Ghosts and even worse in Titanfall. I was seriously about to give up and post when I realized what the problem was.
So of course I switch to fast and now I am 30-1 in Ghosts, among others. And I'm not even what you'd call a very good COD-style player. I mean, it was immediate - all of the sudden I started hitting everything.
So the moral of this story is, don't forget about input lag! If your TV has a "gaming" mode, try it - usually those are faster, for a reason. And even if it doesn't, make sure you turn off post-processing options like FI - any post-processing meant to enhance an image is going to induce input lag, and for games you really don't need them.
I know most players probably know this but as my experience shows it's easy to forget. Your XIM4e will thank you