One of the new features introduced in the Firefox 4+ release is hardware acceleration though it’s not enabled by default. The reasoning is two-fold: the feature isn’t quite fully baked and can introduce some instability – though in practice this is more precautionary in my experience; and secondly, it’s not compatible with all versions of Windows. The GPU hardware acceleration leverages Direct X 10 and is therefore constrained to users of Vista or Windows 7 with a suitable graphics card might be interested in checking out Mozilla’s offering.

From Firefox’s address bar access the about:config preferences backend. Using the Filter box search for all preferences containing render.

Double-click on the key gfx.font_rendering.directwrite.enabled to toggle its value to True.

Locate the preference mozilla.widget.render-mode – if the key does not exist it can be created by choosing New->Integer from the right-click context menu.

Set the value to 6.

With both preferences now set as below, restart Firefox to apply the change. You should notice a nice performance boost when scrolling graphically intense web sites as well as an overall improvement in the font rendering of the browser.

If the results aren’t to what you were expecting, you can revert each change and restart the browser without any lasting implications.