How to record facecam ?

I use Sony Vegas for putting things together. But the only thing I want to know is which webcam recording software has the most highest FPS?

There aren't really any *software* with higher FPS. o_o
Use a generic one like WMM, CyberLInk etc..
If you're having FPS issues, it's about your webcam, not your software.
There could be some settings issues though, so make sure the "Exposure" tab in your webcam settings isn't put on max. It causes lag.