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I Got an AMD FX(tm)-8350 Eight-Core Processor with 4GHz frequency and up to 4,2 GHz Turbo Core speed, but I cant get the Turbo Core to work.

dmesg | grep powernow

should tell me something like:

[ 2.187170] powernow-k8: Found 1 AMD FX(tm)-8150 Eight-Core Processor (8 cpu cores) (version 2.20.00)
[ 2.187204] powernow-k8: Core Performance Boosting: on.
[ 2.187250] powernow-k8: 0 : pstate 0 (3600 MHz)
[ 2.187252] powernow-k8: 1 : pstate 1 (3300 MHz)
[ 2.187253] powernow-k8: 2 : pstate 2 (2700 MHz)
[ 2.187255] powernow-k8: 3 : pstate 3 (2100 MHz)
[ 2.187256] powernow-k8: 4 : pstate 4 (1400 MHz)

but it shows nothing. Checked if powernow-k8 is loaded via modprobe, and it is. Turbo Core and APM are enabled in BIOS, Cool n Quit also.

cpufreq-info

tells me that

driver: acpi-cpufreq

is loaded, but maybe it should be powernow-k8 like I saw on other posts. May that be the issus why Turbo Core is not working, and if yes, how can I change the driver to powernow-k8?

I use Ubuntu 14.04 with newest Kernel.

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The module "acpi-cpufreq" is correct. powernow-k8 has been deprecated since linux 3.7. (Archwiki has it all =-) https://wiki.archlinux.org/index.php/Powernow#CPU_frequency_driver )

According to Phoronix (http://www.phoronix.com/scan.php?page=article&item=amd_fx8150_features&num=1) your CPU should be running at it's full speed, but the turbo frequency is just not displayed on linux for some strange reason. The article is kind of old now (from 2011), and I expected that that sort of issue would have been solved by now, but I guess I was wrong...

Here is another example that it is working, but the values are not being outputted correctly: Launchpad Bug #1071434, comment 50

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  • Thanks for your fast answer. I checked it myself and you were right, cpufreq-aperf shows 4160000 as speed. – user264593 Apr 2 '14 at 15:59
  • Glad I could help! – Stunts Apr 2 '14 at 19:43
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[Update 2014-Aug-07]

I published a detailed analysis over at unix-stackexchange.com which contains (at least for me) a few surprises. Such as the ondemand governor potentially being worse than performance (at least with the Richland A10-6700) and fglrx apparently using some questionable tricks to improve short-term boosts, abruptly having to compensate for that in the long run. I'm glad I had a closer look at this.

[Original Answer]

  • The output of cat /proc/cpuinfo does not, and will not, reflect any processor boost. The boost is an autonomous decision on the chip based on potentially complex criteria. Read about it here.
  • The output of cpufreq-info will not show available boost frequencies, but the output of cpupower frequency-info will.
  • The output of cpufreq-aperf (after modprobe msr) is comparable to the output of cpupower monitor. The frequencies shown by these tools are supposed to reflect boosts.

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