A3D alone has a severe impact on performance

Looks like PCI limitation.

Hey!

Thanks for sharing your results!

Interesting results, thanks for sharing. I think the A3D 2.0 cards are best paired with "overkill" CPUs for this reason. Your conroe doesn't look like it had trouble keeping up, but 700mhz PIII or similar might struggle a bit.

Yeah I tried some Half Life with A3D 2.0 awhile back with an Athlon 1000. The frame rate hit wasn't acceptable to me.

I know this is an old thread, but this is the most recent discussion I could find on the topic of AU8830 revisions.

Is there any known difference between B0AAAA and B0AAAB revisions? I just realized that not all of my B0 revision SQ2500s were exactly the same.

I know the SQ3500 exists (though all the pictures of it seem to be gone from Vogons and the rest of the internet), but is it safe to assume that the B0AAAB is the last revision of the SQ2500 and therefor the last product shipped by Aureal? I wonder what changes they were making to it as the business was coming to an end.

AFAIK, it's just a silicon refresh. There aren't any feature or major design changes in the chip. There is a change from the 8830A2 to the 8830B0 in which the internal data bus timings were changed to avoid an 8-cycle WaveTable data fetch stall in the A2 rev. This is why the SQ2500 runs faster, especially in WaveTracing titles, since all reflections are ran through the 64 WaveTable channels.
The stalls in the A2 are avoidable though if they wrote the drivers to move the VDB WaveTable channels so they aren't processed until later in the audio chain.

Long ago (time flies!) I did some preliminary tests in Win98 and remapped the VDB audio chain in the 2041,2048 and 2050 drivers, and saw no speed difference between the SQ2500 and MX300 once I did, however this level of hacking caused random issues whenever the A3DAPI wanted to rework the VDB chain.

There are major differences though between the AU8810, Au8820 and AU8830, although the designs are based on the same core ideas.

[The reason for the delays in the AU8830A2 rev]
The WT cell contains (per channel) a 2nd order butterworth LowPass filter, Sample Rate Converter, Delay lines, and Mixer (for panning and gain)

The Vortex chips have an internal "Vortex audio Data Bus" (VDB) which chains Work To Do (WTD) in a likewise fashion:
VDB chain for WaveTracing (WT_FIFO->WT_Channel->VDB Bus) Each channel (or a 4-Channel downmix of all the WT channels) can be sent to the VDB, typically this appears at the top of the WTD list, but the Sample Rate Converters in the WT cell want 4 samples to interpolate over with a 2-cycle load delay per sample thus the 8-cycle delay.
Since the VDB processes all cells sample synchronous, but walks the WTD chain sequentially, it stalls the audio processing for 8-cycles while it loads the WT channels with the sample data.
Placing the WT channels at least 4 steps lower in the WTD VDB chain allows the WT samples to load while the other blocks are processing their samples and thus mitigates the delay.
The driver programmers didn't know this and load the WT at the top of the WTD list, mainly for reflection processing.

Aureals solution was to revise the chip so that these delays are no longer an issue and prepare new chips for the SQ3500 release.

Hope this shines some light into the benchmarks differences between the chips.