IME, Chrome is slower in terms of UI responsiveness, especially when starting up (massive disk usage) and switching tabs/making new tabs (pegs at least one core of my CPU, whole browser goes catatonic).
IME chrome is faster when I have enough RAM. I have a notebook with 16G of memory and Chrome runs great on it- seems quicker than Firefox. But on my workstation I only have 8G and usually have more things fighting for it. When memory is low Chrome gets unusable but Firefox keeps going along at its not-quite-as-fast-as-chrome-with-enough-memory pace.