Kernel Streaming

Compared with wave out method, kernel streaming requires less CPU time.

It also bypasses KMixer and Windows volume control.

It has a lower latency.
Drivers like ASIO4ALL use this to bypass Kmixer in XP.

 

It probably won't work with Vista or Win7.

Kernel Streaming is known to work on certain Windows Vista and Windows 7 configurations, but not with devices having WaveRT drivers such as High Definition Audio Devices integrated with newer motherboards

http://www.hydrogenaudio.org/forums/index.php?showtopic=78885