My sound skips/stutters for about half a second (certainly no more than 1 second) on average every 5-20 minutes. I initially had no sound on this computer with Ubuntu 14.04, which is probably because Ubuntu 14.04 has an outdated version of Alsa. I then tested with a live disc of Ubuntu 16.04 (before official release date), which did give me sound. At this point, I installed the the latest version of Alsa onto Ubuntu 14.04 from here (because 16.04 wasn't officially released at the time and I didn't want to take chances with an unstable system):

https://wiki.ubuntu.com/Audio/UpgradingAlsa/DKMS

Sound immediately worked with the latest version of Alsa's driver (March 24, 2016 at the time) on Ubuntu 14.04. However, it came with a cost: this stuttering problem. I then retested with the live disc of Ubuntu 16.04 (this time after the official release date), which also produced sound but with the exact same stuttering problem.

I found that on Ubuntu 14.04, the stuttering problem remains unfixed since the March 24, 2016 release of the Alsa daily driver until at least the version I have installed in this bug report.

These facts strongly suggest an Alsa problem: 1. The problem does not occur at all on Windows, thus ruling out the possibility of a hardware problem. 2. I had no sound at all before installing the Alsa daily drivers, but did have stuttering sound after installing them. 3. The problem persists on Ubuntu 16.04, which suggests the problem is specific to the driver rather than the operating system. 4. The problem occurs whether playing a locally stored media file with a media player installed on my computer or watching an online video, thus ruling out the possibility that the problem is due to a single browser or plugin issue. 5. Is my hardware too new? Probably not. Here are the results of running "grep "Codec:" /proc/asound/card*/codec*":

/proc/asound/card0/codec#0:Codec: Realtek ALC891 /proc/asound/card1/codec#0:Codec: Nvidia Generic

The fact that my card is identified by vendor and chip name rather than ID as specified at https://wiki.ubuntu.com/Audio/HDAGeneric suggests that my hardware is supported. By the way, I'm using the Realtek, not the Nvidia HDMI.

I've tried disabling all unnecessary channels under alsamixer, but that didn't fix the problem. I tried all 3 potential fixes at https://wiki.ubuntu.com/Audio/PositionReporting, but none worked either. I commented my /etc/modprobe.d/alsa-base.conf and /etc/pulse/default.pa files appropriately to show what I tried (I know at least alsa-base.conf is uploaded).

I really appreciate the effort you developers put in to supporting sound on Linux. I hope my bug report will help fix this problem for a lot of users on Skylake systems.

More information and attached files can be found here (I filed a bug report with Ubuntu before I found out about Alsa's developer mailing list): https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1580744