dwardzala
Ah, didn't ever try WASAPI on X3 because it wasn't well executed between Sonar and Windows.
I was using WASAPI with a UA-101 interface and (I think) Sonar X1. Certainly pre-Platinum anyway. Wasapi fixed a looping bug that only affected some ASIO drivers where when loop recording each successive loop got shortened by the milliseconds set in the audio buffer. So loop 1 would be fine, second pass would replace the last 10ms of the loop with silence, 3rd pass replace the last 30ms with silence and so on.
The bug got fixed in an update, but as I recall WASAPI was pretty much identical in performance terms to ASIO, at least with that particular interface.