Benoit Jacob, who works on Mozilla's platform engineering team, spelled out why users should verify that their computers, especially PCs powered by Windows, have the latest graphics drivers.
"When we turned these features on by default in nightly builds around September last year, and then in [Firefox 4] Beta 7, crash statistics and bug reports quickly showed that bugs in graphics drivers were often making these features misbehave," Jacob said in a blog. "We reacted by selectively disabling these new features on buggy drivers, based on the large amounts of information collected by beta testers."
To prevent crashes, Mozilla created a list of graphics drivers that Firefox 4 reads; if a driver is on the 'blocklist', the browser disables hardware acceleration.
Last year, Mozilla added hardware acceleration to Firefox 4. The technology shifts browser page rendering and composition chores from the computer's CPU to its graphics processor.
Mozilla followed in Microsoft's acceleration footsteps in August when it rolled out Firefox 4 Beta 4, the first preview which included the technology.
When Microsoft announced Internet Explorer 9 (IE9) in November 2009, it kick-started the push for hardware acceleration by promising that the new browser would boost page content rendering and composition speeds on Windows Vista and Windows XP.
Unlike IE9, Firefox 4 supports partial hardware acceleration on Windows XP, still the most popular version of Windows. It does that by calling on the Direct3D API, which the old operating system supports, rather than Windows Direct2D and Direct3D APIs, which are available only in Vista and Windows 7.
Needed: A 'very recent driver'
Jacob said that Windows users must have a "very recent driver" if their machine sports an Intel graphics card; version 257.21 or newer for Nvidia cards; and version 10.6 or newer for AMD's ATI-branded cards.
"Unfortunately, certain computer manufacturers do not allow end users to upgrade drivers on their own," said Jacob. "Hopefully these manufacturers will eventually give their users these much needed graphics driver updates."
Mozilla has published a more detailed list of the Intel graphics cards and associated drivers supported by Firefox 4's hardware acceleration.
Firefox 4 on Mac OS X relies on OpenGL to accelerate some aspects of page construction and rendering. Mac users must have Mac OS X 10.6.3 or later to support all Firefox 4's acceleration.
Some graphics cards and chipsets used in older Macs, including the ATI Radeon X1000 and older, nVidia GeForce FX and older, and Intel GMA 950 and older, don't support OpenGL and so won't be able to use the technology. Among the Macs with unsupported graphics are the Mac Mini from mid-2007 (which uses the Intel GMA 950).
Mozilla has ended the Firefox 4 beta cycle, and plans to ship the first 'release candidate', or RC build, of the browser to the public shortly, possibly this week.
"Unless serious issues are found during in-house testing or its cycle of beta testing, this will be what we ship to users," Mozilla stated on its website. "Historically, we have not shipped the first release candidate."
A final version of Firefox 4 should appear this month.