Just wanted to say Thank You!!! New System 10.11.4 on Z97X-UD3-BK/i5-4690K using MB 8.1.0....sound was driving me nuts, tried plist mods, re-installs, all kinds of various stuff. Installed codec commander v2.5.2 (the latest I think as of couple days ago) on a suggestion from another thread and it didn't work... there was some kind of weak sound after sleep (not usable) and the optical port was illuminated but the speakers would now pop every so often now, very annoying...then I went to remove it and oh yeah SIP...so how do I delete that kext now??..LOL...wow El Capitan is a major PITA. Still trying to figure that out. Sorry not a programmer (hats off to you that are, some of this stuff makes my brain hurt....LOL).
But I found this thread, downloaded the codec commander kext linked here (v 2.40), saw the posts with the guys who said it worked with their Z97x-UD3's (thanks for mentioning that guys!) figured why not give it a try (other system reverting to older versions would sometimes solve issues) maybe it would at least stop the popping. Installed with kext utility which removed the other version and put v 2.40 in, everything seems to be working just fine after many cycles of sleep and restarts, etc.
Not the cleanest way to do it but hey it worked. Awesome!!