By using the built in wav_player (firmware 1.5 and above) I can play wav files pretty easily. However, when I play them from the sd card this causes a lot of stutter. So far I have tried three different SD cards with the same results. I have used the mix.wav found in the res directory and put it on my SD card and run this code.

from wav import *

wav_player.playWav('res/mix.wav')
wav_player.playWav('/sd/mix.wav')

The one played from the memory plays fluently without issues. The one from the SD card stutters and does not run fluently.

Anyone has an idea on how to solve this?

I haven't figured it out either but you could make a connection using PuTTY :

http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

With PuTTY, click on “Session” in the left-hand panel, then click the “Serial” radio button on the right, then enter you COM port (eg COM4) in the “Serial Line” box. Finally, click the “Open” button. With baud rate 115200 I get a terminal. It's either the connection with VS or with the terminal though, less ideal.