Audio performance

Although none of the boards we tested provide true hardware acceleration for 3D audio, Realtek's HD Audio drivers do support more simultaneous voices than its AC'97 drivers. That allows the RDX200 to complete RightMark 3D Sound's 32-buffer test, while the AC'97 nForce4 boards are stuck at 24 buffers. Still, there's little difference between the actual CPU utilization of these audio implementations.

Audio quality
We used an M-Audio Revolution 7.1 card for recording in RightMark's audio quality tests. Analog output ports were used on all systems. To keep things simple, I've translated RightMark's word-based quality scale to numbers. Higher scores reflect better audio quality, and the scale tops out at 6, which corresponds to an "Excellent" rating in RightMark.

The RDX200 comes out ahead in a couple of RightMark Audio Analyzer's quality tests, although it's unclear whether the difference is the board's Karajan audio riser, the presence of a different Realtek codec chip than is on the other boards, or some other factor.