That means it's working correctly. Any other screen recording tool will work the same. That's because it's creating uncompressed video (basically, 24 screenshots/second, or whatever you have it set to).
To reduce size, you need to use a video encoding tool such as Handbrake after you are finished to create some sort of compressed video. It will shrink a lot.
If Fraps recorded and encoded at the same time, you'd have no processing power left to play games.
That's how live video recording like this works. If it compressed as it was recording, it'd be slower. Everybody deals with it, just tossing it into Handbrake when they're done (or it's compressed when exported from the video editor where they added overlays and special effects like all the youtubers like to do nowadays).
http://obsproject.com/ This is the only free one I've found that works properly, but do note that it's a lot slower than just using something like FRAPS alone (since it has no option to save uncompressed like FRAPS and DXTory do), saving locally to h.264. Looks like the project is still alive, it's been updated recently.
Generally you can just drag the video file into Handbrake (yes, dag the file from a folder and drop it onto the handbrake program when it's open, it's quick and easy like that), then go to the Video tab and set the quality to 20 (less is better, more is blurrier), that should be a good enough quality for most things.
To be fair I've no idea if it was updated using ChoidujourNX, but that look like it. I also can't seem to use Daybreak on a SX Core so lol. Also pardon if talking about the switch here makes you uncomfortable