Hi - there's a fully functional solution for the ALC662, it uses a kext I hacked plus a dsdt edit. I use S/PDIF & analog outputs.

Graphics works best [for me] using Chameleon's GraphicsEnabler plus a dsdt edit plus having the extracted ION VGA ROM in root & referenced by Chameleon.

Suggest you boot from a modern Linux BootCD & at a terminal type:

. . . copy this dsdt.aml to a USB stick & attach it to a post here.

When I have a spare moment I'll look through your dsdt, edit where required, & post it back plus the kext for sound & the VGA ROM