MP3's and Quake

I then tried a completely impractical (yet possibly revealing) stress test - simultaneous sample processing and playback. The SBLive uses 8-point interpolation to mix sounds sampled at different rates for simultaneous playback, while the MX300 uses a "more-accurate" 26-point method. To test how well each card could handle multiple streams of audio data, I ran several streams of repeating .wav files through Winamp under the DirectSound decoder (WAV-OUT decoding yielded comparable results, being about 3-5% slower on each card). Half of the streams run were a 16-bit 44.1kHz mono stream, the others were 8-bit 11kHz stereo streams. As you can see from the graphs (forgive my lack of graphical talent), both cards ran neck and neck, with the SBLive holding a slight edge over the MX300 in terms of accelerating DirectSound. Again, the release drivers for the MX300 might address this, but presumably not by much.

Simultaneous DirectSound Streaming Performance

To get an idea of how each card performed under high CPU load, I ran multiple 128kbps, 44.1kHz stereo MP3 files, again measuring CPU utilization. Here, the SB Live appeared to have a much easier time, showing up to 34% less CPU utilization over the Diamond card with four simultaneous tunes. It also easily passed the 12 track test, while the MX300 failed at 8 streams, for some reason complaining that the wav device needed was currently in use. Considering that the MX300 is designed to accommodate up to 92 Directsound streams simultaneously, this is more than likely another driver issue that should be resolved once the card ships.

Simultaneous MP3 Streaming Performance

Since Quake II demands exclusive access to DirectSound, results for the Demo1 test had to be run through the WAV-OUT decoder to allow for simultaneous streams. The game was benchmarked at 640x480, running various .WAV and .MP3 combinations. While it's unlikely that anyone would care to listen to 4 simultaneous MP3s while playing, the results show that despite the disparity in the pure MP3 test, the MX300 and the SB Live post virtually identical scores (again with the MX300 failing the 12 MP3 stream test). Until a game comes out that heavily taxes the capabilities of 3D audio components, it's fair to say that each card holds its own against the other.

Simultaneous Audio Streaming through Quake II