Fraps is the best. Hands down. Bought it, worth every penny.
You need a decent computer of-course, you're essentially taking a screenshot of the screen 30 times a second. Large disk space is required because it obviously can't compress it while it's recording, that would slow it down even more. Splitting the video up into 4GB sections is because it would be impractical to be working with such a large file, so it records it in multiple smaller files.
If you get stuttering it's probably because your HDD isn't fast enough to store so much information so quickly, so turn down your resolution or record at a lower FPS. Likewise with the GFX card.
Honestly, you won't find a better tool.