I made pull request which results in ~150 files which changes, some of files being quite big with a lot of different lines.
While using Firefox 28 on the pull request screen everything hangs for minutes with 100% CPU utilization. On Chrome 33 the pull-request web page is usable, but very sluggish. On Chrome I saw "This diff was too big for us to render on page load. Click here to try to load it" in some places, but in case of Firefox I lost my patience for this to render.