I finally made the sound card work under OS X86 for two PCs. First one is a PowerEdge 400SC. South bridge is Intel ICH5 chipset. The sound card is SoundMax AD1980. It was not working just because of the codec kext. These are the steps I took:

• Download EVEREST from http://www.lavalys.hu/index.php, which is a windows software for checking the Codec ID. I don’t know, but there should be some Linux equivalent out there, I guess. If you are reading this and happen to know, please let me know, thanks. Installing Windows just because of this is not worth.
• Edit “/System/Library/Extensions/AppleAC97Audio.kext/Contents/PlugIns/AppleAC97CodecAD198x.kext/Contents/Info.plist”, add “ADS70 in the Vendor ID list:

  <dict>
      <key>AD198x</key>
      <dict>
          <key>CFBundleIdentifier</key>
          <string>com.apple.driver.AppleAC97CodecAD198x</string>
          <key>IOClass</key>
          <string>AppleAC97CodecAD198x</string>
          <key>IOProbeScore</key>
          <integer>10000</integer>
          <key>IOProviderClass</key>
          <string>IOAC97CodecDevice</string>
          <key>PNPVendorID</key>
          <string>ADS70 ADS75 ADS74 ADS73 ADS72</string>
      </dict>
  </dict>
  

• Reboot and it works fine. My PCI ID is 8086:24D5

The other one is ridiculous. It’s an ECS 848P-A motherboard. South bridge chipset is also Intel ICH5, with Realtek ALC655 (somehow “lspci” on linux doesn’t list it, but I figured it out by looking up the manual of the mobo). It was not working when I first attempted just because the jack was bad, or at least it now appears so. I used the jack on the front panel and now it’s working. I tried both Windows and Linux and it’s always the same case so I assume the jack is bad, not os x. I bought this board refurbished when my old 865 board went bad. The sound card probably never worked properly but I never struggled coz I had a couple of extra SB Live PCI cards.