I’ve found that Firefox 4 doesn’t seem to have complete hardware acceleration enabled by default and by using the following tweaks have improved performance.
1. Go to Firefox:Options:Options:Advanced
Make sure “Use hardware acceleration when available” is ticked
2. Go to about:config and add or change the following
mozilla.widget.render-mode : 6
gfx.font_rendering.directwrite.enabled : true
webgl.force-enabled : true
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