Hi Puttabong,
I had exactly the same problem as WinLinMac01. Actually the ALC850 is working fine with the AC97 driver (as far I remember I did choose the driver while installation) but from time to time the sound gets lost.

I hadnt the patience to examine how to fix this. Instead of that I bought the cheap USB audio adapter which works ootb with the C-Media driver. I know this isn't the solution most of us expect but I know from my Linux-experiences with non compatible hardware that's not worth the time you have to spend with googling for solutions if a supported one costs this little amount of money.

But - if you guys have any hints how to solve the lost sound problem I would appreciate as well!

Best regards