I honestly find the opposite. Facebook's website seems to be one of the best ones of this new SPA trend, and doesn't seem to have any speed issues. The (android) app meanwhile consistently lags for me, and things like voting on polls have a 50/50 chance of working.
Huh. I guess I forgot about it. My browser has touch.facebook come up if I type in the URL bar and I've basically only used the touch version even on desktop for ages.