Try:

• http://support.microsoft.com/?kbid=2454826 (performance and functionality update for Windows 7)

I got the error "This update is not applicable to your system". I chose to install the x64 Windows 7 version. By the way, I have SP1 installed.

Also, I tested this out in Safe Mode. Firefox 4 RC1 WORKS with Hardware Acceleration enabled just fine. However, I boot into normal windows and the fonts are FUBAR again. Does this tell us anything?

While in Safe Mode, all advanced Windows features are disabled, and so is Direct2D.

Here's a screenshot showing the difference for me on Windows 7 with ClearType enabled.

The Direct2D version has different font sizes, spacing, and less-defined letter shapes.

I have this same problem, but I'm seeing strange graphical glitches when setting gfx.direct2d.disabled to true. It doesn't happen all the time; often when I'm doing something with a menu. When it does happen, it usually either goes away by moving the mouse around, reopening the menu, or refreshing the page. I added 2 pictures to show what I'm talking about. The first shows it just happening in a menu, the second shows it happening in the entire window. (edit: other way around)

This graphical glitch only happens when gfx.direct2d.disabled is set to true.

I'm using windows 7 64 bit, HD 5850 video card with 11.2 version drivers.

I couldn't find anyone else with this specific graphical problem when using this setting, so if there is another thread somewhere with more info about let me know.

I solved it, just enable the setting "gfx.font_rendering.directwrite.enabled" to enabled in "about:config"

and restart

then done