This is pretty obvious, but maybe someone else hasn't noticed yet.
NVIDIA drivers feature a so-called ShadowPlay function. I records in Full-HD (or simply full resolution) with H264 codec and 60 frames per second (makes it very smooth and fluid and you can also directly upload to Youtube in 60fps!). The compression is choossable in quality and the highest quality setting (the one I tried) looks pretty amazing and is still pretty compact at that. Totally outperforms Fraps and similar crap. Zero lags or stuff, too. (Although admittedly I have very quick gear CPU wise)
Just in case someone wants a quick render and not bother with MME and stuff like that. ShadowPlay you just set basic settings, output folder and shortcut and then you press your shortcut button each time something cool happened (it retroactively records 5 minutes or so, depending on how you set it and probably what your gear allows).