Mainboard: Gigabyte GA-7N400Pro2 rev 2.0
Chipset: nVidia nForce2 Ultra 400
Audio Codec: MCP, ALC655
Manufacturer: nVidia, Realtek
Channels: Up to 6 via analog, 2 via digital. Also supports HRTF downmixing of 5.1 to headphones.
Output Sound Quality (1 to 10): 8
Compatability: 85%
MIDI synth: None (old drivers had a DLS synth built in, but it's since been dropped)
MIDI I/O: Supported via a joystick bracket pin header on the motherboard, but GigaByte didn't include a bracket. Additionally, these brackets are hard to find because every manufacturer uses a different pin assignment on the pin header.
This is the more or less the same chipset as on el_pusher's ABIT NF7 2.0. You can run either nVidia's drivers on it (which takes advantage of the on-board nVidia MCP sound hardware upstream of the Realtek codec chip) or Realtek's (which bypasses the nVidia MCP hardware and talks directly to the ALC655), but the nVidia drivers currently seem to have better compatibility (despite being released less recently). Here's a good place for drivers, although this version is new since I last checked: www.planetnvidia.com./modules.php?name= ... load&cid=2
I haven't noticed too many problems in games. World of Warcraft doesn't take advantage of my center speaker (5.1 setup) unless I use a registry tweak that artifically creates the center channel (this may be Blizzard's fault and not nVidia's however). You do have to have patience in tweaking the sound settings in some games to find the right comination of hardware acceleration, EAX, DirectSound3D, etc. settings to get good compatibility. The EAX support in both nVidia and Realtek drivers is intentionally below the level required by games that Creative pays to have EAX support specifically added to, but I don't miss it (3D positional audio, which is almost always supported via DirectSound3D even without EAX, is more important to me).
A note on the headphone downmixing: nVidia includes an option called "CineSurround" (which I think is similar to Creative's CMSS3D or whatever it's called) in which you can run a game in 5.1 speaker mode but have the mixer downmix it to stereo with simulated 3D positioning that would be appropriate when using headphones. In my opinion it doesn't sound all that great (my Logitech Z-5500d speakers do the same thing automatically when I plug headphones in, and they seem to do a much better job). Still it's kind of nice if you often play games with headphones on.
Also, recent versions of the nVidia mixer are buggy and have a memory leak (uses up all your memory if you leave it running for several days).
I should also mention that there's no way I'd buy a Creative PCI sound card to replace my on-board sound, as Creative's cards just don't offer anything useful over my current solution. I'm considering buying a third-party PCI sound card with DDL (Dolby Digital Live) support though.