Fraps uses little CPU, there is another solution that uses no at all CPU and has identical quality - but it's costy. It's having another PC and a capture card inside of it, so it captures everything the first PC is displaying without the first PC lagging.
It uses plenty if it's an old CPU. I saw some new software out there, so I was wondering if it may be better in that department.
Recording is a hard task. Software will not make it better .