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AMD Overdrive - CPU temperature vs. Core temperatures

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  • Aug 7th, 2011 3:42 pm
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Aug 30, 2003
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AMD Overdrive - CPU temperature vs. Core temperatures

Hey all,

Recently upgraded my comp to the following:
Asus M4A88T-M/USB
AMD Phenom II x4 945 3.0ghz (c2 stepping, 95W version)
4gb Mushkin silverline
HD4860 1gb ddr5
Hyper 212 Plus cooler (with a slower speed fan I had lying around. When I used the stock fan, it had a whining noise which was annoying me).
1 back case fan

In the attached image, it shows the CPU temperature higher than my core temperature. I was wondering which one I should be considering when overclocking. Image

AMD says max temp for this chip is 71C:
http://www.cpu-world.com/CPUs/K10/AMD-P ... IBOX).html

I had prime going for about an hour with a slight overclock to 3.2 ghz and core temp went to about 42 and cpu temp went to 59, which is when I decided to stop. So i'm wondering if I have still had a lot more room to go.

Thanks in advance.

Regards,
Mint
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Aug 15, 2010
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Mississauga
Core is the important one.

But why is your speed only running 800 mhz? That should be running 3.0 Ghz unless you underclock it.
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Jun 16, 2003
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Brampton, ON
Its AMD power saving, it downclocks cores to 800mhz
[OP]
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Aug 30, 2003
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Ironsmack wrote:
Aug 5th, 2011 1:20 am
Core is the important one.

But why is your speed only running 800 mhz? That should be running 3.0 Ghz unless you underclock it.

Cool. Sounds like I've got a bit of room to work with for OC then. For the 800mhz, that is the cool and quiet program underclocking as noted by nerdonsite.

Anyone know what the cpu temp is?
Member
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Feb 7, 2011
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Mirabel


Yes, with intel processor. It's know that you look at the core temp 'cause they are higher.
But with AMD, the core temps are actually around 10 or 15 C below the cpu temp. So, the core temp of amd is a calculated value (reason why sometime it goes below the ambient temperature).

So:
For AMD, Look at the cpu temp.
For Intel, Look at the cores temps.
[OP]
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Aug 30, 2003
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spikexp wrote:
Aug 5th, 2011 11:24 am
Yes, with intel processor. It's know that you look at the core temp 'cause they are higher.
But with AMD, the core temps are actually around 10 or 15 C below the cpu temp. So, the core temp of amd is a calculated value (reason why sometime it goes below the ambient temperature).

So:
For AMD, Look at the cpu temp.
For Intel, Look at the cores temps.

Hm.. that just made thing more confusing :|

So for AMD, they calculate the core temp. Not sure why they didn't just follow intel.
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May 26, 2002
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Mint wrote:
Aug 5th, 2011 3:14 pm
Hm.. that just made thing more confusing :|

So for AMD, they calculate the core temp. Not sure why they didn't just follow intel.

A few things about AMD temperatures. First nobody knows what the "real" temperature AMD CPU runs at. This is because of a few reasons.

First AMD doesn't have temperature diode in each core... they actually don't even have a diode in the core, there is only 1 thermal diode and its located in the Northbridge. So you can't get any true core temperature because the diodes not on the core real temperature of core should be hotter then what the diode reports.

Secondly, AMD doesn't provide temperature offset information for there CPU like Intel does (t-max). Without that information you can't calculate the 'real' temperature you can only report what the value of the thermal diode is providing. If the thermal diode is giving a reading of 30 C the 'real' temperature could be 40C, 45C, 60C, 70C, nobody knows but AMD. That is why all these programs are reporting core temperatures lower then the motherboard temperature (and often times lower then ambient which is impossible unless you believe your CPU is an air conditioner).

if you don't believe me, you can look it up in AMD's white paper for there Phenom CPU's. Or if you believe the maker of Core Temp here's a few of his quotes:


"Core Temp displays the temperature reported to it by the CPU.
I've explained it many times, these processors report temperatures which are not absolute. There is usually a 10-15C delta that should be added to the readings to see the real temperature value.
You can also see how HWMonitor reports the same readings under the Phenom title."


-LeeBear
[OP]
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Aug 30, 2003
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So if my 'cpu temp' is at ~42C idle, my actual core temp is probably higher.

I'll probably hold off on OC'ing for now as it's quite fast as it is.
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May 26, 2002
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Mint wrote:
Aug 7th, 2011 2:08 am
So if my 'cpu temp' is at ~42C idle, my actual core temp is probably higher.

I'll probably hold off on OC'ing for now as it's quite fast as it is.

I wouldn't worry to much about what your "actual" core temp is. The important thing regardless of what CPU you use (intel/AMD) is how close you are to the Thermal Limit of that CPU. Your Phenom has a Thermal limit of 71 C (not real temp but what the maximum value of the thermal diode gets to before shutdown) I'd say you'd be pretty safe to run the CPU around 60-62 C (on load) without any worries. Don't worry to much about idle temperatures since it doesn't really matter and the thermal diodes are less accurate at lower temps anyways.

-LeeBear
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