OpenAL & OpenAL-soft

Hi all!
I have a question.
In some games (for example Warzone 2100) I have problems with sound - terrible stuttering. After googling this problem, I have found, that it uses OpenAL.
I see, that OpenSUSE has too versions of OpenAL - OpenAL and OpenAL-soft.
So, my question: why 2 vertions? whats the difference? And what should I use?
Pulseaudio was removed, of course.