WindowsXP Drivers for Digigram VXPocket 440

I'm using the 4in/4out Digigram VxPocket440 PCMCIA audio device under WindowsXP, and trying to understand some issues related to the various supported drivers. There are 3 options: DirectSound, WMME/Wave, and ASIO, all supported by MaxMSP.

With the latest drivers from Digigram, I find that the performance of the DirectSound and WMME drivers eats up app. 20-30% of the CPU time (in the system), as indicated by the WindowsXP performance monitor (this is NOT the CPU% displayed by the Max DSP window, which remains at 0% in all cases described herein). This is a huge chunk to take off the top of CPU availability before any application processing even begins to take place. In both of these cases, the WindowsXP performance manager indicates that Max itself is using only 0-3% of the CPU.

When using the ASIO driver, the situation of system CPU usage improves tremendously: the WinXP performance monitor shows the system CPU% at virtually 0%. However, the MaxMSP usage displayed by WinXP has now soared to 50-60%! This is with no processing whatever being done in Max... with only audio in/out enabled (and, as previously stated, the Max DSP window shows 0% CPU usage).

I'm trying to understand why the ASIO driver seems to transfer the CPU usage to Max, which would appear to eat up twice as much CPU as the Digigram DirectSound and WMME drivers. Anyone have any insights as to what's happening here?

Donald Swearingen