Re: nforce 5 (550/570) running on Solaris?
I'm running Solaris Express build 45 on an ASUS M2N-E with Nforce 570 Ultra. It didn't need any special drivers or modifications. The gigabit and SATA interfaces work just fine. I'm using it as a server so I can't speak to the audio.
AMD x2 4000
ASUS M2N-E (0302 bios)
512MB DDR2 533 (you'll want at least 1GB)
1 PATA, 2 SATA drives (zfs is great!)
matrox millenium video card
note: this board is extremely picky on RAM!