I just upgraded to a newer machine, HP AMD Quad Core running LinuxMint Mate 17.
inxi -C reports CPU: Quad core AMD Phenom II X4 B95 (-MCP-) cache: 2048 KB flags: (lm sse sse2 sse3 sse4a svm)
Just tried for the first time watching video feed from the net via Youtube and other sources and I am getting freezing and stuttering(same sound repeats over and over). It seems that if I move the mouse around the screen rapidly I can reduce the severity of the problem, almost as if the system is not being kept busy enough. I tried opening System Monitor to see what was going on but it is showing very low levels of activity and also seems to freeze when the video freezes.
I shut the machine down and went into the Bios and turned off multi cpu and the same video from Youtube seems to be OK. Any thoughts on how to solve this problem without always having the other three cpus shut down all the time?

Also tried looking at a DVD with VLC Media Player and that is also stuttering.

a) i swear i've seen a very similar problem (sound stuttering gets better when the system is under stress. i think it was here on LQ.

b) as a workaround, you can start a program and tell it to run on a particular cpu via some shell variable, so you'd have to enter something like "CPU_NUMBER=0 firefox" (this is not the actual command, please search).

1 members found this post helpful.

Tried using taskset to lock Firefox to CPU0 while running burnK6 on CPU1 to help load system but it didn't help. I was thinking that this might be a video driver problem so using another hard drive I loaded an older version Mint 13_64 so that I could try the AMD fglrx-legacy driver but that didn't work either, maybe slightly better but not OK. Could this be an audio driver problem instead?

on that other thread it was an audio problem. i found it!
http://forums.debian.net/viewtopic.php?f=7&t=114502
have a close look, it says at some point that op's sound gets better when he starts 3 virtual machines.
it also links back to similar threads on LQ.
this should give you something to do.

fwiw, i don't think you need taskset to set cpu affinity - setting a shell var should be enough.
i don't remember the variable, but as an unrelated example of how it works:(this would start firefox with an alternate gtk theme)

Should I be asking this question in a different forum perhaps? I tried going back to the Windows 7 disk that came with this system and which presumably uses all 4 CPUs and it plays the DVD fine with VLC. VLC also plays perfectly in LinuxMint if I disable the other 3 CPUs via the BIOS. To me this sounds less and less like an audio or video problem and more like some sort of kernel timesharing issue?

I would try some live CDs or other distros preferably not related to *buntu and without pulseaudio. See if it also occurs there.

did you actually read what i gave you?
there's a LOT of information in it, and it really seems very close to your problem.

of course posting on linuxmint forums can't hurt; but mint is based on ubuntu is based on debian, so debian forums is not the wrong place to search for solutions.

Yes ondoho I did read it plus a lot of other stuff but it didn't provide any real answers. I decided that the idea of trying another distro was probably a good one so I downloaded openSuse 13.1 and installed it on a spare drive. It still uses pulseaudio, I'm not sure there are any distros that don't anymore.
Anyways I can't get vlc or the resident player to play my DVD, probably codec issues or something I can't seem to resolve. After installing the flashplayer plugin I can watch youtube videos in Firefox. With all 4 CPUs working it does not freeze and the audio does not stutter but the video (top and bottom) is jittery. With only one CPU the video seemed to jitter for a couple of seconds and then stabilized.
I tried the inxi -Fxz command to see exactly what it says it's using but the output is unreadable due to the colours they're using in the terminal screen and I can't figure out how to change them. After years in the Red Hat/Fedora and Debian style worlds I'm not finding openSuse to be very user friendly I'm afraid.
Other checking shows that it is running the ati,radeon video driver though and the kernel is 3.11.6-4-desktop and Xorg is 1.14.3.901.

Then it is probably not audio, it may be video driver related.

I figured what the heck lets try some other distros as well. Fedora 20 plays the youtube video completely stable but I couldn't easily fix vlc codec problems so moved on. Suprisingly Ubuntu 14.04 from which Mint17 is derived also plays the youtube video perfectly. After codec issues vlc also plays the DVD perfectly. here are the results of inxi -Fxz for both Mint 17 and Ububntu 14.04

Mint 17_64
inxi -Fxz
System: Host: Lotland Kernel: 3.13.0-24-generic x86_64 (64 bit, gcc: 4.8.2) Desktop: N/A(s/b Mate) Distro: Linux Mint 17 Qiana
Machine: System: Hewlett-Packard product: HP Compaq 6005 Pro MT PC
Mobo: Hewlett-Packard model: 3047h Bios: Hewlett-Packard version: 786G6 v01.11 date: 08/04/2010
CPU: Quad core AMD Phenom II X4 B95 (-MCP-) cache: 2048 KB flags: (lm sse sse2 sse3 sse4a svm) bmips: 23938
Clock Speeds: 1: 800.00 MHz 2: 800.00 MHz 3: 800.00 MHz 4: 2300.00 MHz
Graphics: Card: Advanced Micro Devices [AMD/ATI] RS880 [Radeon HD 4200] bus-ID: 01:05.0
X.Org: 1.15.1 drivers: ati,radeon (unloaded: fbdev,vesa) Resolution: 1024x768@85.0hz
GLX Renderer: Gallium 0.4 on AMD RS880 GLX Version: 3.0 Mesa 10.1.0 Direct Rendering: Yes
Audio: Card: Advanced Micro Devices [AMD/ATI] SBx00 Azalia (Intel HDA) driver: snd_hda_intel bus-ID: 00:14.2
Sound: Advanced Linux Sound Architecture ver: k3.13.0-24-generic
Network: Card: Broadcom NetXtreme BCM5761 Gigabit Ethernet PCIe driver: tg3 ver: 3.134 bus-ID: 3f:00.0
IF: eth0 state: up speed: 100 Mbps duplex: full mac: <filter>
Drives: HDD Total Size: 80.0GB (16.5% used) 1: id: /dev/sda model: WDC_WD800JD size: 80.0GB
Partition: ID: / size: 24G used: 5.5G (25%) fs: ext4 ID: /home size: 46G used: 6.9G (16%) fs: ext4
ID: swap-1 size: 4.19GB used: 0.00GB (0%) fs: swap
RAID: No RAID devices detected - /proc/mdstat and md_mod kernel raid module present
Sensors: None detected - is lm-sensors installed and configured?
Info: Processes: 174 Uptime: 1 min Memory: 339.7/3449.4MB Runlevel: 2 Gcc sys: 4.8.2 Client: Shell inxi: 1.8.4


Ubuntu 14.04_64
System: Host: Lotland Kernel: 3.13.0-32-generic x86_64 (64 bit, gcc: 4.8.2)
Desktop: Gnome Distro: Ubuntu 14.04 trusty
Machine: System: Hewlett-Packard product: HP Compaq 6005 Pro MT PC
Mobo: Hewlett-Packard model: 3047h Bios: Hewlett-Packard version: 786G6 v01.11 date: 08/04/2010
CPU: Quad core AMD Phenom II X4 B95 (-MCP-) cache: 2048 KB flags: (lm sse sse2 sse3 sse4a svm) bmips: 23938.8
Clock Speeds: 1: 800.00 MHz 2: 800.00 MHz 3: 2300.00 MHz 4: 800.00 MHz
Graphics: Card: Advanced Micro Devices [AMD/ATI] RS880 [Radeon HD 4200] bus-ID: 01:05.0
X.Org: 1.15.1 drivers: ati,radeon (unloaded: fbdev,vesa) Resolution: 1024x768@85.0hz
GLX Renderer: Gallium 0.4 on AMD RS880 GLX Version: 3.0 Mesa 10.1.3 Direct Rendering: Yes
Audio: Card: Advanced Micro Devices [AMD/ATI] SBx00 Azalia (Intel HDA) driver: snd_hda_intel bus-ID: 00:14.2
Sound: Advanced Linux Sound Architecture ver: k3.13.0-32-generic
Network: Card: Broadcom NetXtreme BCM5761 Gigabit Ethernet PCIe driver: tg3 ver: 3.134 bus-ID: 3f:00.0
IF: eth0 state: up speed: 100 Mbps duplex: full mac: <filter>
Drives: HDD Total Size: 80.0GB (4.9% used) 1: id: /dev/sda model: WDC_WD800JD size: 80.0GB temp: 31C
Partition: ID: / size: 70G used: 3.7G (6%) fs: ext4 ID: swap-1 size: 3.76GB used: 0.00GB (0%) fs: swap
RAID: No RAID devices detected - /proc/mdstat and md_mod kernel raid module present
Sensors: System Temperatures: cpu: 26.9C mobo: N/A
Fan Speeds (in rpm): cpu: N/A
Info: Processes: 195 Uptime: 8 min Memory: 958.1/3449.4MB Runlevel: 2 Gcc sys: 4.8.2
Client: Shell (bash 4.3.11) inxi: 1.9.17

Sorry I forgot to add that given they're both running the same Xorg, video driver and sound driver I don't think this is an audio or video problem. Am I right?

What video driver were you using originally when the stuttering occurred ? I mean currently you seem to be using radeon, not fglrx.

The two system reports show my starting point of LinuxMint 17 (to which I have returned) where the problem originates and a load of Ubuntu 14.04 on a spare hard drive which operates without problems. An attempt to use fglrx did not solve the issue.

If you suspect a kernel issue, compare the two kernel configs.

I got the respective config files from /boot and compared them line by line, all 127 pages, using LibreOffice Writer as it gave me the best control over where I was in the document. There were not a lot of differences and most of them were to do with hardware I do not have.
The ones that might be significant are:

Page 3
"#CONFIG_MEMCG_KMEM is not set" is replaced in Ubuntu by "CONFIG_MEMCG_KMEM=y"

Page 9
"# CONFIG_ZBUD is not set" is replaced in Ubuntu by "CONFIG_ZBUD=y"
"# CONFIG_ZSWAP is not set" is replaced in Ubuntu by "CONFIG_ZSWAP=y"