Both of they have a freeware trial version. Bandicam allows you to record unlimited time but with watermark, you can remove it purchasing the full version. Fraps trial allows you to record 30 secs and with watermark. And the program makes a video with a size of 1GB every 3 mins so you need space in your HDD. Both of they slow your PC, fraps can slow it to 15%. And you need a good PC to record good(decent) videos. I have tested both of they, freeware, and bandicam slows the PC more than fraps, but the only con is the watermark
And there is a thread about this just with the same name, I think that we know how to use the search option
Greetings
Ivan