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Joined: 25 Sep 2007
Posts: 378
Location: Canada

PostPosted: Tue May 20, 2014 6:25 pm    Post subject: What measures core temp on fx-8350 (Solved) Reply with quote

Widespread wisdom on "the web" indicates that the amd fx-8350's core temp should not exceed 61degC and the socket temp about 10deg more.
My question is this: Using lmsensors viewed via gkrellm, which if any of the sensors indicates these temps?
(Note I am currently overclocking to just short of 4700MGHZ and running x264enc as a load test)
Likely candidates:

(1) Socket temp: it-8721-hwmon3/temp1 This currently reads 59degC

(2) Core temp: k10temp-hwmon2/temp1 This currently reads 43degC

My intellectual problem with this (especially (2)) is that the k10temp is alleged to be a composite of various temps that are used in controlling power management etc,
so it doesn't claim to be the core temp. Moreover, when newly booted, (2) shows ridiculous values such as 6degC.

Question: Can I take the k10temp highest value as a proxy for the core temp. i.e. so long as k10temp <=61degC can I assume that I am operating with a safe core temp? And more immediately With these temps would it be safe to try to overclock to 4800GHZ?

Last edited by nlsa8z6zoz7lyih3ap on Thu May 22, 2014 2:40 am; edited 1 time in total
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Joined: 14 Apr 2014
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PostPosted: Tue May 20, 2014 7:50 pm    Post subject: Reply with quote

k10temp is indeed the value you want to use, but you have to keep several things in mind:
- as you already know, this is not the core temperature
- none of these sensors is made and calibrated to function well in low temperature ranges, they only have to be accurate in the higher range to provide a somewhat precise temparture for the emergency shutdown system

For my system (Phenom II X6) I usually take that value and add a safety measure of 10°C, never had problems with that.
If you can safely overclock to 4800 MHz is not only dependent on the current temperature, but also on different factors:
Can your CPU run without failure at 4800MHz with the current voltage?
If not, which influence has the higher voltage on your temperatures?

In short, if you can safely run at 4800MHz can only be determined by you, but don't expect much additional performance from a 100MHz step, there are surely other bottlenecks in the system that are more worthwhile to tinker with.
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Joined: 23 May 2008
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Location: Dallas area

PostPosted: Wed May 21, 2014 10:55 am    Post subject: Reply with quote

I used to add 10 when I was running my x6 processor.

It will give you false readings when doing that to fx chips though

Max temps for all FX processors are
Socket = 70c
Core = 61c (and as you already know, this one is not accurate until the 40c mark is reached)

These are max and if run at this temp all the time can lead to a shortened life.

I've overclocked my chip to 4.0ghz on standard voltage just by changing the freq multiplier and leaving voltage alone.
I was running appx 10deg above case temp (temp0) at idle,
Then I turned the ondemand gov on and it now runs 4-5 above the case temp at idle.
It ramps up when needed and stays relatively cool when not doing much.

Gaining an extra 100mhz is fine (bragging rights mostly) but you wouldn't notice it in general use.
There are some that have pushed the 8350 to just over 5ghz, but that depends on the individual chip, MB and cooling.

Note: the k10 temp is not temp per se, but a sliding scale variable, based on things happening in the chip, which is why it starts becoming accurate past 40 deg C.
Asus m5a99fx, FX 8320 - nouveau, oss4, rx550 for qemu passthrough
Acer laptop E5-575, i3-7100u - i965, alsa
5.0.13 zen kernel, profile 17.1 (no-pie & modified) amd64-no-multilib
gcc 8.2.0, eudev, openrc, openbox, palemoon
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Joined: 25 Sep 2007
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Location: Canada

PostPosted: Thu May 22, 2014 2:40 am    Post subject: Reply with quote

Many thanks to TobiSGD and to Anon-E-moose for their replies. These answer my primary question in a clear and helpful way, so I am going to mark this as solved.

Since they posted their responses I have tried some experiments regarding overclocking and list the results below:
(These involved various altered settings of cpu and mbo/cpu voltages, memory speeds and voltages, cpu multplier and and mob frequency.)

(1) The overclock to 4.7GHZ mentioned before runs stably, as far as I can see, on all progams.
(2) Past this, x264-enc segfaults and or xorg freezes the system within a few minutes to /1/2 hour.

However I actually made this computer with the purpose of it being a work station to simultaneously run 8 instances of a particular
program, with varying data input, 24/7 for extended periods of weeks or months. (This program uses no floating point real data types) If I disable all graphical output and run everything from the basic login text console things gets interesting.

(3) I can stably run this program at 5GHZ with the socket temp <=60 and the k10 temp <=52. These programs produce output about 25% faster than they do when run at the default 4GHZ settings. So I think that this is a benefit to me for this program. However with the sole exception of this program, even overclocking to 4.7GHZ (The highest which appeared to be stable for everything) produced no subjectively noticeable benefit to me regarding anything that I actually care about.
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