ALSO onscreen recording software?

[Bridge]

I dunno if you are looking for a free software but the program I use is Mirillis Action! and its great. It makes HD quality .fic file formats so theres no drop of framerate. It can also record desktop or region. After that you can export it in many formats or upload it right to Facebook or YouTube. It can also record audio. Too bad it isn't free but you can still google it and see the program (there is an month trial also)

It has nothing to do with the file format*. Recording gameplay footage (especially in HD) takes up a disgustingly large portion of your random access memory (if it's too low) and puts a lot of strain on your hard drive because you are probably reading everything (the OS and game + all the programs used) off of it plus writing to it at the same time. Unless you have a monster HD you are going to experience a drop in FPS. The only effective way, I've heard, to overcome this is to set up a new hard drive or a new partition (I've heard this does not usually work) to distribute the stress more. External hard drives don't work because the I/O rate of USB devices is too low to record footage smoothly.

*Though the compression codecs the program uses to write the video data has a significant effect, with HD footage I just don't buy it.