My fixed background made scrolling the site very slow, what can I do to improve it?

I had the same problem and solved it using this jQuery plugin : http://srobbin.com/jquery-plugins/jquery-backstretch/

It doesn't use any CSS3 property but it works fine and doesn't have any performance issue on Chrome 13 or Firefox 6.

I thought I would just contribute here. Rather than use background-attachment: fixed; use :before and position: fixed; problem sorted. I ran into this same problem.

Read more here: http://fourkitchens.com/blog/article/fix-scrolling-performance-css-will-change-property

The problem goes away for me when I remove the background-size property. I think it was the scaling of the large image that was causing the problem. If that doesn't work, just remove the background image altogether. However, I've never heard of a large background image causing lag before.