What Sacred 2 are you running (e.g. base Fallen Angel, with Ice & Blood expansion, Sacred 2 Gold)?
FYI, the only thing Sacred 2 and Sacred 3 have in common, is the word "Sacred" in the title.
Sacred 2 Fallen Angel - no expansion packs
Update :
I just tested this game (patched to the same level) on Windows 7 32bit on a Dell E6430 ATG laptop with an Intel integrated display adaptor and 8Gb Ram (32bit OS only allows use of just under 4Gb but anyway..). Whilst idling at the menu screen with the waterfall, after a minute or so, the same stuttering of video and sound occurred but was not terminal, after a few seconds of this, the animation and ambient sound resumed.
Both machines only show increased system memory use of about 500mb - certainly it does not MAX out the system memory.
Point taken on Sacred 3...
Unbended looks to be the preferred way forward, I need to read more...