but for now, that choppy sound may just be due to codecs. If the sound was choppy all the time then that could be caused by many things. I'm no tech, but the things I would look at are failing sound card, bad leads to the speakers, loose connections, or may be a bad driver.
Here's another one, when was the last time you spring-cleaned your computer? I don't know if it is a laptop or PC, but have you cracked open the case recently and looked inside? Dust will kill electrical components, and sadly computers are great dust collectors. Here's a video on how to clean a grungy PC;
But if the sound is only choppy some of the time that may point to something else, eg codecs for particular sound track files, ( http://en.wikipedia.org/wiki/Audio_codec ).
Or, may be there are too many applications or processes running on the system.
Not knowing anything about your computer there is not much more I can say, but I did see this on the Realtek web site;
"High Definition Audio Codecs
Audio drivers available for download from the Realtek website are general drivers for our audio ICs, and may not offer the customizations made by your system/motherboard manufacturer. To be sure you obtain the full features/customizations provided in your original audio product, please download the latest drivers from your system/motherboard manufacturer's website."
I don't know what an IC is, (something card?), but it seems likely you may need to check with the motherboard maker's web site, or if this a computer from a major retailer, Dell, HP, etc, check with their site.
You're right about the lack of driver details for this ALC888S, which Realtek calls an audio codec.
I had thought that drivers and codecs were different, so I think I have to pass on this now, and suggest you seek help from experts, either at the PC Hardware forum or the Home audio & video forum.
As to Windows 7, there is more information and help on this at the Windows 7 forum.