This is an addition to the full AMD on OS X 10.6 guide. Don't use this information if you do not own an AMD 880 or 890 motherboard.
AMD 8xx with OS X 10.6 - Solutions and experiences
I made this topic for people who are experiencing troubles while installing a retail Snow Leopard on their AMD 8xx chipset system.
All solution I came across during my search will be posted here, and explained in an easy to understand way.
Problems with booting and installing
Disabling AMD C1E
This is the most common solution; disabling the AMD C1E option in your BIOS. This particular option enables the use of C1E stepping for your processor, which obviously does not work in OS X and it seems that it breaks the kernel.
Using an older Gigabyte 8xx BIOS
Is your system powered with a Gigabyte AMD 8xx motherboard? There is a chance that you are using a BIOS version that does not work with Snow Leopard for some reason. BIOS versions until FC5 are reported working, so if you are using FC6 or later it won't work anymore. A solution to this is reflashing the BIOS to the older FC5 one. A simple Google search with the keywords Gigabyte + [motherboard] + BIOS FC5 would probably do the trick. But be aware of the risks! If not done properly, you could end up with a non-working motherboard!
Using the SATA 3 connectors
Having an Still waiting for root device error? First make sure that the SATA mode in your BIOS is set to AHCI. Done and still having the same error? Check if your SATA HDD is plugged into the blue SATA3 ports. This is a solution mainly for Gigabyte owners as the SATA6 ports tend to be buggy and mostly don't work.
with Sleepenabler and IOUSBFamily
Getting sleep to work on AMD can take some of your time. On an AMD 8xx chipset you'll need a version of Sleepenabler for your current Snow Leopard version (eg. 10.6.8) and patched IOUSBFamily. Sleepenabler has to be placed in /Extra/Extensions and IOUSBFamily in /System/LIbrary/Extensions. After installing, make sure to rebuild the caches with Kext Utility.
The simplest solution for having audio on AMD is VoodooHDA. Unfortunately there is only one working version of the VoodooHDA kext for AMD 8xx, and that would be this one. Installation with Kext Helper.
Succesfully installed your system with or without this tiny guide? Post your experiences here and help other people installing OS X on their systems! Spread the word!