What is the best FREE game recorder for pc?

I'm talking about things like wegame/xfire/fraps(but it costs money). Keep in mind my specs... I have a dual core i5 maybe 3.something ghz...but everything else is good like 6gb of RAM and a decent graphics card... also, I don't care too much for crazy awesome quality but just fluency... I really just don't want it to crash my game whenever i start or stop recording... THANKS