ASIO is a protocol which allows the software to control your sound input/output directly to and from your hardware (soundcard) without the need to use "directsound" (from directX AKA MME) as its protocol...
Basically the ASIO protocol allows your software to interact (directly) with your hardware. This is an absolute to musicians and sound engineers because it reduces the latency (lag) , that windows would take up in calculating what it wants to send and receive from the soundcard , or indeed from any external sound device.
MME is a slower set of drivers, and could be causing the delay... I was reading other forums for this, since I do not have your device, it would be impossible for me to give details so let me link the other forums here so you can maybe get a better idea.