I don't have the exact numbers on hand, but the game I worked on saw a similar 10-20% increase in daily pageviews as an immediate result of making the site fast

I don't have the exact numbers on hand, but the game I worked on saw a similar 10-20% increase in daily pageviews as an immediate result of making the site faster. I would optimize a few core pages or add more capacity and, like magic, traffic would jump the next day.