stuttering when using two audio cards

Recently I started using PCI sound card (2) for speakers because I didn't like the sound of the built-in sound card (1). But I didn't turn built-in (1) off, I used it for earphones and microphone to talk in skype without reaching for sockets each time. To make volume controls on the keyboard work for speakers I made PCI card default one. After that a bug in teeworlds appeared:
Sound and music start to stutter after some time in the game. "tr-tr" on the default audio card (2), no sound at the other one (1) (no sound of teeworlds, aimp3 sounds fine if i chose the correct audio card in options).

Computer is fast enough to run teeworlds. Programs running: Hamachi, Lingvo x5, Kaspersky, Vmware, AIMP3 and others.