The latest update for Google Chrome for OSX has a rendering issue where web pages render once upon load and never again. The bug completely prevents the user from properly interacting with a website because it won’t re-render a page after it loads. The issue seems to only affect iMacs.
You can replicate this bug by loading a webpage, then resizing the browser window. If the entire browser becomes white then the problem affects your browser.
Until Google pushes out a fix we’ve been downgrading our machines to the previous stable release.