Linux also supports HD Audio controllers, as do the OpenSolaris, FreeBSD, NetBSD and OpenBSD operating systems. macOS has full support with its AppleHDA driver. There are UAA drivers for Windows 2000 and Windows XP SP2 as well. Microsoft Windows XP SP3 and later Windows versions include a Universal Audio Architecture (UAA) class driver which supports audio devices built to the HD Audio specification. Users requiring more audio I/Os will typically opt for a sound card or an external audio interface, as these devices also provide additional features that are more oriented towards professional audio applications.
Motherboards typically do not have any more than eight onboard output channels (7.1 surround sound) and four input channels (back and front panel microphone inputs, and a back-panel stereo line-in). However, as of 2008, most audio hardware manufacturers did not implement the full specification, especially 32-bit sampling resolution. The Intel High Definition Audio specification includes the following features:
