Real Temp - New temp program for Intel Core processors

[unclewebb]

@uncle: the latest version is the 2.79.8 right?

That's correct. Intel didn't release enough information at the August IDF for any software developer to accurately translate DTS data into meaningful temperature numbers so I've decided to slow down development. Too busy overclocking!

Dua|ist: I've been reading about this on the E8500 forum but there's a problem with a lot of the data that's been gathered. Here's a link to the X-Bit article. It's easier to read in English!

http://www.xbitlabs.com/articles/cpu...duo-e8600.html

Intel has documented that their 45nm sensors used in the Atom chips have plus or minus 10C of error at 50C. Slope error implies that as a CPU cools down, the amount of error would increase even further. If review sites or individual users do nothing to try and compensate for this then their reported temperatures or conclusions are meaningless.

X-Bit has decided to ignore the "slope error" and error at TjMax that these sensors have.

Their power consumption numbers are interesting but not consistent. It doesn't make sense to me that at idle and full load at default MHz that power consumption is identical for C0 vs E0 but when overclocked there is a 9 watt difference. I would need to see some more test data with more processors before I'd conclude anything. I'd use Prime95 small FFTs for consistent power usage. I have a wattage meter on my computer and I know it can float around a watt or two.

If the 9 watt difference is 100% accurate then that might translate into a 1C difference at full load but probably not into the differences that some users are seeing. Most of the differences that I've seen posted are more related to sensor error than anything else.

If you have a similar C0 and E0 then why not run them at the same FSB frequency and use the same multiplier. Use RealTemp and calibrate them at low MHz / low voltage so they both report about 5C above room temperature. Set them back to fully overclocked at the same MHz and core voltage and then compare Prime95 small FFTs full load temperatures. That would be interesting and a little more scientific than the X-Bit testing.

[Dua|ist]

Those E0 And C0 that you compared did they have same VID?

Nope, but they were pretty close. The C0 8400 had VID = 1.225v while current E0 8500's VID is 1.25v

unclewebb: Thanx for the link. I see your point. But first of all we're talking about temperatures at load around 70C (whichever Tjmax they used, this is much above the 50C, so no "slope error" here, right?).
And then if we assume their measurements are correct, -9W actually seems not that small difference, and it resulted not in -1C but in +2C according to their testing, which is what confuses me most.

That C0 is not mine anymore but I might ask to play with it a little more. Problem is, this 8500 E0 has both sensors stuck at anything lower than 36C, so no clue how'd I calibrate it. But right above those 36C both sensors show same temperatures. The C0 8400 (calibrated) would heat up to ~70C under Linpack at 4.16GHz @ 1.400v (CPU-Z under load), the current E0 8500 heats up to ~73C at 4.3GHz @ 1.344v (CPU-Z again). I must admit I'm a little afraid pushing 1.400v through this one given the current temps, and thus can't set the E0 to same clocks & volts as C0.

[unclewebb]

But first of all we're talking about temperatures at load around 70C (whichever Tjmax they used, this is much above the 50C, so no "slope error" here, right?).

That's what I used to believe but that's not what Intel said at IDF. Their version is that there is some error at TjMax and slope error goes from one end of the temperature graph to the other which makes sense based on how temperature sensors work.

They called the amount of error at TjMax 'X' which is somewhat useless information but does confirm that there is some error and TjMax is not a fixed, written in stone number. Perhaps X means about plus or minus 5C. You might think that plus or minus 5C is way too large an assumption but that is actually a tighter tolerance than what Intel lists their 45nm Atom sensors at when tested at 90C.

If you put a handful of processors in a 70C oven and ignored the slope error for the moment, they could indicate anywhere from 65C to 75C based on the data coming from the on chip digital thermal sensors. If you take into account slope error then the temperature range might even be a little wider than that.

What I'm trying to say is that we're all putting too much faith in the quality of data coming from these sensors. The 45nm sensors are far worse than I ever imagined. How can you possibly compare temperatures when there is such a huge amount of error in these readings?

And then if we assume their measurements are correct, -9W actually seems not that small difference, and it resulted not in -1C but in +2C according to their testing, which is what confuses me most.

That just confirms that uncalibrated temperature readings are worthless. If power consumption goes down then the core temperature will also go down. If it doesn't, then either the core temperature reading is not accurate or the power consumption number is not accurate or maybe both.

I did some testing today while running Prime95 small FFTs and an 8 watt reduction in power consumption at the plug was resulting in a 2C drop in core temperatures. That's with a Tuniq Tower on high at 4000 MHz and a core voltage of 1.40 volts. I tried to keep everything as equal as possible and used the Clock Modulation feature to switch back and forth between a duty cycle of 87.5% and 100%. This reduced power consumption by about 8 watts while still maintaining the same CPU frequency and voltage while running Prime95 small FFTs. That might not be 100% scientific but it's probably pretty close. The CPU temperature was in the low 50C range while testing.

I've always found that if a Core CPU is running too hot then Prime95 small FFTs will fail or LinX will fail or your computer will re-boot. Too hot depends on how hard you are pushing things. The harder you overclock and over volt, the cooler you'll have to run to maintain stability. If you are overclocking then your temperatures will be nowhere near the thermal throttling or thermal shut down point so there's no need to worry about what temperature you're at. It's just a number and for most people that are unable to calibrate due to sticking sensors or simply don't bother, it's not even a very accurate number. Overclock as high as you want and let stability be your guide.

[burebista]

It's just a number and for most people that are unable to calibrate due to sticking sensors or simply don't bother, it's not even a very accurate number. Overclock as high as you want and let stability be your guide.

Word bro.

[davidk21770]

...
I did some testing today while running Prime95 small FFTs and an 8 watt reduction in power consumption at the plug was resulting in a 2C drop in core temperatures. That's with a Tuniq Tower on high at 4000 MHz and a core voltage of 1.40 volts. I tried to keep everything as equal as possible and used the Clock Modulation feature to switch back and forth between a duty cycle of 87.5% and 100%. This reduced power consumption by about 8 watts while still maintaining the same CPU frequency and voltage while running Prime95 small FFTs. That might not be 100% scientific but it's probably pretty close. The CPU temperature was in the low 50C range while testing.
...

Why doesn't someone with water cooling and a water coolant temperature reading, drop vcore and clock as low as possible and then run tests with heated water to see how the sensors compare to the water temp. If everything's as low as possible, there shouldn't be much difference between the water temp and the cpu temp.