Unnecessary-Paints by Paul Lewis http://www.html5rocks.com/en/tutorials/speed/unnecessary-paints Attach a scroll handler that will disable hover effects and set a timer for enabling them again once the user has stopped scrolling.

expensive-scroll.js

// Used to track the enabling of hover effects
var enableTimer = 0;

/*
 * Listen for a scroll and use that to remove
 * the possibility of hover effects
 */
window.addEventListener('scroll', function() {
  clearTimeout(enableTimer);
  removeHoverClass();

  // enable after 1 second, choose your own value here!
  enableTimer = setTimeout(addHoverClass, 1000);
}, false);

/**
 * Removes the hover class from the body. Hover styles
 * are reliant on this class being present
 */
function removeHoverClass() {
  document.body.classList.remove('hover');
}

/**
 * Adds the hover class to the body. Hover styles
 * are reliant on this class being present
 */
function addHoverClass() {
  document.body.classList.add('hover');
}