New answer July 2016!
I believe the latest Realtek drivers, sourced from a strange, password-protected area of the Realtek corporate site, fix this. Don't ask how I got these files - the important thing is I think I've found a working solution. It's been about an hour and I haven't noticed the issue once yet.
Because I don't trust the net, you can download an archive I've compiled here. It includes three things:
- Installer for the latest (July 2016) Realtek HD Audio driver. It works with my Asus GL551JW without issue, and it uninstalls other drivers it finds in the process.
- A file called rtkhdaud.dat. This needs to be placed into C:\Windows\System32\Drivers. It will disable the Realtek power management, which is supposed to be useful but actually causes constant popping noises and cannot be disabled via any intuitive means
- A readme documenting an optional registry key fix for the above (I'm not sure which one works, but the two seem to when used together).
Install the driver, copy the file, make the registry change. This will incur about fourteen reboots. After this, everything should FINALLY work properly. This also means users with headsets plugged into their ASUS laptops should now regain headset mic support that was lost when using the Dell driver I posted in a different answer. I'll be keeping that one online in case this solution fails to help people.
"fourteen reboots", this is a mistake. Its a loop, to fix this follow this guide http://kunmii.blogspot.pt/2015/08/solution-realteks-audio-driver.html.
