Well, yes, when it comes to High Definition AudioService Pack 3 is the last major refresh Microsoft will make available for Windows XP, released at the end of 2001. In mid December 2007, on the heels of Windows Vista Service Pack 1 RC1 and Windows Server 2008 RC1, the Redmond company also opened up to the general public the first public release of XP SP3. In fact, you will be able to grab your very own copy of Windows XP SP3 Release Candidate 1 via this link. But of course, be advised that despite the RC label and the proximity to RTM, the download is still a beta, with all the inherent shortcomings.
But on top of the caveats associated with the XP SP3 RC1 testing development build, the service pack is apparently in need of fixing when it comes down to High Definition Audio. This scenario is nothing new to Windows XP, having survived from the RTM version of the operating system and through SP1 and SP2. So far, XP users have had to add High Definition Audio support to the operating system by installing the Universal Audio Architecture (UAA) High Definition Audio class driver. This is valid not only for XP SP1 and SP2, but also for Windows Server 2003 and Windows 2000 with Service Pack 4. And reports now claim that the same is valid with the Release Candidate of XP SP3.
"UAA describes a class driver initiative for computer audio solutions that are supported in Microsoft Windows operating systems. An audio device that is UAA-compliant can rely on the operating system for driver support. Therefore, hardware vendors do not have to supply a custom driver for a device. A High Definition Audio device complies with the Intel High Definition Audio specification. A High Definition Audio device connects to the PCI bus or to the PCI Express bus. A High Definition Audio device can reside on an internal audio card, or the device can be part of an integrated motherboard chip set", Microsoft informed.
Apparently, the Redmond company has failed to include the Universal Audio Architecture (UAA) High Definition Audio class driver by default into Windows XP SP3 RC1. There is no telling whether Microsoft will do so by the time it will make available the final version of XP SP3. However, in the meantime, Dashken offers a work-around. But be advised that the fixes delivered are in no way supported by Microsoft, or by the official releases from the Redmond company.