Why do you suggest using the ASIO4ALL drivers for Audio passThru with Windows?
The best solution for low latency in Windows is the ASIO system. ASIO is a communication object that bypasses the Windows Media System to allow an application to directly communicate with the drivers.
Unfortunately, although ASIO satisfies the need for low latency with Windows systems, it does have another shortcoming. Only one ASIO Comm object can be executing in the system at any one time.
We investigated solutions to this problem and discovered that the team from ASIO4ALL solved this problem some time ago in an elegant and easy to use way. ASIO4ALL is stable and typically delivers comparable (or in some cases better) performance than device dedicated ASIO comm objects and also allows Windows users to create an aggregate ASIO device out of multiple compatible audio peripherals.