M Dot or RWD. Which is Faster? outlines some great research conducted by Doug Sillars on whether m-dot or responsive sites are faster. Redirects slow m-dot sites from the very start while those sites might turn out to be lighter in requests & KB weight (potentially due to incomplete experiences, I’d argue).
But what is really interesting is the idea that RWD sites are VERY competitive on Visually Complete and SpeedIndex scores. The median values are within 5% for both metrics. Even though it appears that RWD is faster, there is enough fluctuation in the data that we should probably call it a dead heat.
Be sure to read the full post. It’s well worth your time.