Hi,
I skimmed through this thread for two reasons...first of all, I'm a huge digital audio fanatic in some aspects...I'm also conflicted in the fact I hate digital audio comparted to it's grandaddy analog. Most of this stems from the fact that I see the standards for digital audio (if there are any) to be quite lacking....but I love digital in that it's easy to work with and can sound really good IF you've got the knowledge to assemble everything.
I've not dealt with the 889A, but my previous laptop had I believe the ALC883 chip. Either way, the main differences between the Realtek HD Codec chips seems to be mostly input and output capabilities. The Realtek chips themsevles aren't too bad, but here's the thing i'm surprised no one came up with....a LOT of the times, the quality of the analog output stages after the audio codec are what hurt a card. People tend to forget that despite the fact it's an digital system...at SOME point there's analog circuitry involved.
This is the case I've seen on most sound cards. You'll have a mediocre codec chip that's backed up with the cheapest opamps with circuits that aren't of optimum design, and honestly, I've ot had a card I haven't modified. Onboard sound, while added as a convience and selling point to the board...generally doesn't follow a high standard of audio quality. Sometimes you get outputs that sound ok, sometimes you get some that sounds bad. PCI cards aren't much of an exception either. A lot of times a maker will focus so much of a percentage of card cost to the DSP/Codec that they'll still slap on a basic analog stage that "works".
Despite the fact the ALC's are nice chips....I can't really say go for the Audigy 2...and here begins my spiel on the entire audigy series and other problems with sound cards.
I own an Audigy 2...I actually have one currently in my Linux desktop; and just so you know my credentials and history; my card before this was an audigy 1, and at one point I was a proud owner of a X-Fi.
The Audigy2 may or may not be a better choice over your onboard. Shocked? Here's why. First and foremost, the analog stage on the Audigy is good...better than most...but in audiophile sense it's still subpar. I've actually taken mine, replaced the opamps and using the existing board made a few modifications to the output stages to improve it to quite a fine card. But even with a top-notch analog output, the A2 still has problems. Yeah, the drivers are antique...which is why I started using the kX Project drivers for it. While these drivers are a bit consuming and "much" for a sound card, I have to say...I love the fact that I can create effects by chaining them together in a visual editor...plus you're able to route two seperate stereo outputs to other channels creating a virtural sound card...I mean, they truely unlocked the power of the card. But, the A2 is still based on functionally the same DSP core as the A1. The 96/24 support was "bolted on" in the form of the p16v chip. When feeding the card 88 - 192/24, it basically hands decoding over to this chip. If you're running DSP effects, a version is sampled to 48/16 and fed to the dsp then mixed with the p16v output. If you're playing back 44.1/16...then the DSP still upsamples in hardware to 48/16, it's this conversion that's not done very well and can cause a lot of intermodulation distortion. When I ran my A2, since most of my music playback was done in Winamp, I'd turn the DSP off effectively in the kX drivers and use an SSRC plugin to upsample everything to 96/24. So, if you're using the card "out-of-the-box", you're not getting it's full potential. The original analog stages are good enough for most people....so MOST of the advantage is taken from using the different drivers and changing a few ways you use the card...however, there's a lot of software you couldn't do that with so you still lived with resampled audio. Mind you I honestly don't know what the current state of the kX project is.....I haven't used the A2 in windows in probably about 3 years.
The X-Fi solved this problem in a couple of ways...first, the new DSP core was entirely redesigned and ran the effects at a higher rate (it was capable of 96/24 DSP effects), but had an entirely redesigned resampling process. That's part of the reason the thing has different "modes", changing the mode doesn't just change the mixer interface but it actually changes the processing mode in the DSP...entertainment put more in to resampling and enhancement effects...game put more into EAX 3d and other audio virtualization processes...music creation mode I'm honestly not sure exactly what that did. That seemed more like a "full manual" control more than anything. You had the ability to enable "Bit Perfect" mode which seemed to entirely bypass that nice expensive DSP chip and ran the DAC's at source rate for direct decoding/recording...but you could also access a lot of the EAX stuff from within it....although the mixer software was more scaled toward low-latency mixing...that's actually the mode I left mine in most of the time.
So, for out of the box operation...both are probably a toss-up. The A2 is nice, but it's really just a high-end consumer card and, onboard sound chips have rapidly caught up to it in quality...but you have the question of how good are the analog stages on the mobo and how shielded are they? While a PCI card is still physically connected to the bus, it's components are slightly further away from any interference sources. The A2 has that resampling issue where as I'm not sure what the deal is with the Realtek chips. Part of me wants to say the A2 is a better choice....but I'd really have to sit and listen to the onboard sound from that model of mobo because the quality of ALC, as I stated, does tend to vary between implmentations.
Best advice I can give....take your best stereo system...hook your PC up to it..listen for a while with the A2, listen with the Realtek....listen to various things....then go with the one you like better because, seriously, not everyone hears exactly the same and in the end...all that matters is that you enjoy it.