Comment 8 for bug 744808

This is the comment about that bug by AaronP, a Nvidia Linux Driver developer, maybe it helps:
" I took a look today, and it appears that Firefox is using an enormous pixmap that exceeds the GPU's maximum rendering dimensions, causing software fallbacks. While we will attempt to make it as fast as possible, performance would be greatly improved if Firefox would render using surfaces that fit within the maximum renderable dimensions."
Also see: http://www.nvnews.net/vbulletin/showthread.php?t=152295