Mini MP3 Recorder 1.0 is a quite simple program that doesn´t consume many resources. It lets you record sounds that are captured via a microphone or internally, like thosse sounds captured by the sound card (players, programs, videos, games, etc).
These recorded sounds can be saved in MP3 or WAV formats, and has certain tools to reduce noise and thus improve recording quality.
Thus you can have all the sounds that interest you in MP3 or WAV.