In the box below is a sharing link for each matchup you've tried. Beneath the link is the data for that matchup in CSV format.
It looks like one of the websites you're trying to load does not want their content to be displayed inside an iframe, and is actively trying to bust itself out.
Because of this, it's going to be hard to get an accurate comparison. Please either speak to the authors of the website or try a different matchup.
See why these pages are fast or slow using GTmetrix, a free service that examines your site and gives recommendations for how to make it faster.
webpagetest.org is a community tool for testing and comparing sites using donated locations across the world. You can even create a video of multiple sites loading side-by-side.
Select serial mode to load one side at a time to eliminate the possibility that the two sides will interfere with each other.
whichloadsfaster is a fun way to spread the word that web performance matters. It's about friendly competition and about testing in everybody's browser, not just ones that have nice performance tools already.