I see a lot of claims that ASIO gives lower latency than the WDM/KS option. With some interface drivers, this may be so, but it's easy to set WDM/KS unfairly.
With ASIO, your latency will be down to the soundcard drivers DMA buffer size. The smaller this is, the lower the latency. However, you can get pops and clicks if this is too low and also greater CPU usage of the driver (and less CPU available for plug-ins!).
WDM/KS depends on Sonars own latency settings AND the soundcard buffer. To get the lowest with WDM...
Set the soundcard buffer to its minimum.
Drag Sonars latency slider to minimum (full left)
Ensure "Buffers in playback queue" is 2
Run the Wave profiler.
You may now adjust the performance by dragging the latency slider higher whenever you please without changing the soundcard buffer again.
Many soundcard drivers are WDM with an ASIO interface (the ASIO "driver" is not entirely seperate software). With these, there really should be very little measurable difference in performance between WDM/KS and ASIO.
Some drivers are not truly WDM standard and are pure ASIO, with adapter code that can provide some functionality for Windows audio and WDM/KS. Performance with these should be obviously better if you use ASIO.
Knowing Motu's track record with Windows drivers, I'd suspect it works better with ASIO.
