I might have found a hint as to from what the freezes on my machine were caused. Apparently, freezes took place when the soundtrack track was changed. This may or may not be correlated to the fact that I was running another application in parallel producing sound output (namely Winamp). After disabling sound output by pausing the sound track player and setting volume to 0, I did no longer experience the minute-long freezes (there still occur brief stutters as described in other forum posts, though).
So maybe audio output is sth you should have a look into. My audio setup is rather uncommon, admittedly: I am using a Asus Xonar DX sound card along with a DolbyDigital-Live encoder.