Temperature discrepancy - e4400

omnizzle

Member
Jun 19, 2007
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Hi,

I recently built a new rig, and had originally intended to overclock it. I've tried several cpu temp monitoring programs, and I'm confused with the results. I've heard Speedfan is off by 15C, but I've also heard that TAT is also wrong. Here are the results:

RMClock - approx 30C
Speedfan - 29C
TAT - 43C
Core Temp - 44C

If the latter 2 are the correct temperatures, I won't be able to overclock. I'm relatively new to all this, so help please!
 

JD50

Lifer
Sep 4, 2005
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Originally posted by: omnizzle
Hi,

I recently built a new rig, and had originally intended to overclock it. I've tried several cpu temp monitoring programs, and I'm confused with the results. I've heard Speedfan is off by 15C, but I've also heard that TAT is also wrong. Here are the results:

RMClock - approx 30C
Speedfan - 29C
TAT - 43C
Core Temp - 44C

If the latter 2 are the correct temperatures, I won't be able to overclock. I'm relatively new to all this, so help please!

I have the exact same problem, except I can't get RMClock or TAT working for me in vista 64. See this thread for some good responses. Try everest as well, all of my temp monitoring programs are about the same, except for core temp, which leads me to believe that core temp is about 15c to high.
 

Accord99

Platinum Member
Jul 2, 2001
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The reading from a C2D sensor tells you how many degrees from the throttling point the CPU currently is. So actually, SpeedFan, TAT and CoreTemp are all reading the same value. The difference comes from SpeedFan using a value of 85C as the throttling point while TAT and CoreTemp use a value of 100C for most E4000 series processors, thus giving you the 15C difference in the reported temperature.

At this point, nobody really knows who is right but the main thing is that even with a Core Temp reading of 44C, you have roughly 56C before the CPU begins throttling. So, don't worry about the reported temperature (it probably isn't correct), only worry about how far away the CPU is from throttling.
 

JD50

Lifer
Sep 4, 2005
11,832
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Originally posted by: Accord99
The reading from a C2D sensor tells you how many degrees from the throttling point the CPU currently is. So actually, SpeedFan, TAT and CoreTemp are all reading the same value. The difference comes from SpeedFan using a value of 85C as the throttling point while TAT and CoreTemp use a value of 100C for most E4000 series processors, thus giving you the 15C difference in the reported temperature.

At this point, nobody really knows who is right but the main thing is that even with a Core Temp reading of 44C, you have roughly 56C before the CPU begins throttling. So, don't worry about the reported temperature (it probably isn't correct), only worry about how far away the CPU is from throttling.

When getting 3 different temps, CPU, core 1, and core 2, which is the more important one, the core temps or the CPU temp?
 

omnizzle

Member
Jun 19, 2007
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I tried everest and it said my cpu temp is 1C.... >_>. So do you guys recommend that i OC, even with the seemingly high temps?
 

Accord99

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Jul 2, 2001
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Originally posted by: JD50
When getting 3 different temps, CPU, core 1, and core 2, which is the more important one, the core temps or the CPU temp?
Generally, I would go with the core temp readings, they should be consistent regardless of the motherboard and they respond quickly to changing loads. I find the CPU reading is dependent on the motherboard, and in some cases (like with a P5B dlx I have) updating the bios can change the CPU reading.

The exception is the new G0 stepping, I have a E6750 that even when overclocked to 3.6GHz reports core temps that are lower than ambient when idle. I'm not sure how to interpret these impossible values yet.
 

Accord99

Platinum Member
Jul 2, 2001
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Originally posted by: omnizzle
I tried everest and it said my cpu temp is 1C.... >_>. So do you guys recommend that i OC, even with the seemingly high temps?
Does Core Temp 0.95 indicate that your E4400 has a Tjunction of 100C. If it does, then your temperatures aren't that high since Core Temp thinks 100C is your throttling point and a reading of 44C gives you lots of room to work with.
 

Accord99

Platinum Member
Jul 2, 2001
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Originally posted by: omnizzle
Yeah, it says Tjunction is 100C. So that's good? I should be able to OC just fine then..?
It's just how Core Temp calculates the reported temperature. Tjunction - sensor reading = reported temperature. It means that Core Temp's reading of 44C indicates you have 56C before the CPU throttles. So long as you stay a reasonable value below the throttling point, the OC should be safe.
 

JD50

Lifer
Sep 4, 2005
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Originally posted by: omnizzle
I tried everest and it said my cpu temp is 1C.... >_>. So do you guys recommend that i OC, even with the seemingly high temps?

Hell yes you should OC if your cpu temp is only 1C...:p
 

JD50

Lifer
Sep 4, 2005
11,832
2,610
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Originally posted by: Accord99
Originally posted by: JD50
When getting 3 different temps, CPU, core 1, and core 2, which is the more important one, the core temps or the CPU temp?
Generally, I would go with the core temp readings, they should be consistent regardless of the motherboard and they respond quickly to changing loads. I find the CPU reading is dependent on the motherboard, and in some cases (like with a P5B dlx I have) updating the bios can change the CPU reading.

The exception is the new G0 stepping, I have a E6750 that even when overclocked to 3.6GHz reports core temps that are lower than ambient when idle. I'm not sure how to interpret these impossible values yet.


Cool, thanks, that helps a lot.
 

omnizzle

Member
Jun 19, 2007
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Originally posted by: Accord99
Originally posted by: omnizzle
Yeah, it says Tjunction is 100C. So that's good? I should be able to OC just fine then..?
It's just how Core Temp calculates the reported temperature. Tjunction - sensor reading = reported temperature. It means that Core Temp's reading of 44C indicates you have 56C before the CPU throttles. So long as you stay a reasonable value below the throttling point, the OC should be safe.

er, sorry for the noobish question... what exactly is the throttling point?
 

Accord99

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Jul 2, 2001
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Originally posted by: omnizzle
er, sorry for the noobish question... what exactly is the throttling point?
The throttling point is the temperature where the C2D begins to throttle itself, by reducing its clock frequency and voltage to try to lower the temperature. The assumption is that this temperature is where it becomes dangerous for the C2D, so if you stay a reasonable distance away from the throttling point, your temperatures should be safe.
 

omnizzle

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Jun 19, 2007
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When I load my cpu with TAT it shows the temps at 60C. I've read that the max safe temp for e4400 is around 60C. If/when I OC, what should I use as a referencing point to see if it goes over that point, since theres no real accurate number?
 

Accord99

Platinum Member
Jul 2, 2001
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Originally posted by: omnizzle
When I load my cpu with TAT it shows the temps at 60C. I've read that the max safe temp for e4400 is around 60C. If/when I OC, what should I use as a referencing point to see if it goes over that point, since theres no real accurate number?
The 60C refers to Tcase, which is the temperature at the top-center of the IHS but you can only measure this by placing a sensor under the heatsink. TAT like Core Temp gets the reading from the sensor within the core itself. The danger point for this sensor is the Tjunction value, which in your case is 100C. So stay below 90C as measured by Core Temp and TAT and it should be fine.

TAT will also indicate when the CPU is throttling so you'll know instantly if the temperature reaches an unsafe point.
 

Accord99

Platinum Member
Jul 2, 2001
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I would say the guide is not accurate in regards to CPUs with a TJunction of 100C. The approximation that TCase = TJunction - 15C is unproven, and MB readings are highly variable and aren't useful as a Tcase reading. The guide also doesn't work for the new G0 stepping CPUs.

I believe my own observation is simpler and more useful, which is to stay a reasonable distance away from the TJunction temperature and it's safe. What the actual temperature is, is not relevant since it's probably not accurate anyways.
 

nova2

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Feb 3, 2006
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"accord: What the actual temperature is, is not relevant since it's probably not accurate anyways."

i don't know the accuracy of mine (no laser reader with me), but it works well enough for me.

you are right tho, as most people wont need to care about core temp due to EIST (assuming the CPU isn't near max load most of the time).