We find that estimate far too aggressive, since 24X CD-ROM drives have been shipping in volume for less than two years. Another DAE problem involves SCSI drives running under Windows 98. In an effort to ship Windows 98 on time, Microsoft had to cut some features from the operating system. Another problem for USB speakers concerns the connection of analog audio input. Certain video capture and TV tuner boards might need to connect to USB speakers through analog inputs.
Microphones also pose connection problems without sound boards present.
USB subsystems from different manufacturers aren't handling these issues uniformly. A serious concern for USB speakers involves PCI or AGP graphics boards that continually tie up the system chip set's output buffers. Misbehaving graphics drivers can cause interrupts in USB audio playback. Microsoft's USB sound system checks for this behavior during its installation process and includes a discussion of the problem in its Readme file. Other USB speaker vendors don't highlight or test for this problem.