I used so many, but the best by far is the "free" Shadowplay (except you cannot hide the recording indicator when taking screenshots aaaarg). I say free as Hellshade mentions you need to pay out for a decent Nvidia card
GeForce TITAN, GTX 700, GTX 600, GeForce GTX 800M, GTX 700M, select GTX 600M
I used
D3dgear
Fraps
PlayClaw
Bandicam
DXtory
Action
and more - all of them have problems in some regard.
Fraps for example can show an on screen icon for recording, but if you want to remove it during recording you have to press the button 5 times to cycle it off, and back to on in the same corner of the screen. Nuts. I asked the author if he could make it just a simple on/off toggle but he refused at least twice
. Also recording is raw so files are enormous. This is tricky if you need quite a lot of footage to go through so end up keeping Hard drives full of stuff until you no longer need it.
Playclaw was great nice on screen /on fly config menu but has some quirks with CFS3 sound.
Bandicam needs you use a certain DX swap method with DX games (maybe it will work better with DX mod now?)
D3DGear was about the best of the software ones for me. Forgot what the downside was so far.
Shadow play however is the ultimate.
http://www.geforce.co.uk/geforce-experience/shadowplay