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  #21 (permalink)  
Old March 9, 2010, 09:45 AM
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Tj Max is the temperature the cpu will throttle at.It is an internal on die temp.

The thermal specification is the maximum external case temperature.

Now obviously , these are very different things.Typically Tj max is about 20-30 degrees higher than the thermal specification.

There is debate about the whole maximum temperature issue , but here's the only thing you need to know : Operating your CPU above the thermal specification voids the warantee.

Here's some more reading on it :

The Truth about Temperatures and Voltages - Overclock.net - Overclocking.net

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  #22 (permalink)  
Old March 9, 2010, 09:59 AM
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Even if temps were above temps specified... overclocking it void the waranty anyway!
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  #23 (permalink)  
Old March 9, 2010, 10:05 AM
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Haha....fair enough.

It's really a reliablility issue.Hot parts die faster.

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  #24 (permalink)  
Old March 9, 2010, 10:08 AM
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Yeah I know that.... the watercooling bug is comming I think ;)
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Old March 9, 2010, 10:10 AM
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Watercooling is fun !

This is not a bad time to have the bug, there is enough parts for sale to build one or two loops on this forum right now !
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  #26 (permalink)  
Old March 9, 2010, 10:14 AM
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Quote:
Originally Posted by Charloz24 View Post
Yeah I know that.... the watercooling bug is comming I think ;)
Haha I just started watercooling last December to keep my folding rigs at decent temps.

The Program strikes again!!!!
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  #27 (permalink)  
Old March 9, 2010, 10:51 AM
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75C is nothing for an i7. Considering an i7 920 will break that temperature on stock cooling when under full load. Actually when running bigadv temps were just shy of 90C. Thermal specification is not the max suggested temperature. I wouldn't start worrying temps until you start breaking 90C. You are much more likely to damage CPU's from voltage than w/ heat as they are designed to take extremely high temperatures.
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  #28 (permalink)  
Old March 9, 2010, 11:25 AM
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Quote:
Originally Posted by lowfat View Post
You are much more likely to damage CPU's from voltage than w/ heat as they are designed to take extremely high temperatures.
I would say infinitely more likely, as the only way to damage an Intel CPU with heat would be to take a blowtorch to it.
Quote:
Originally Posted by BrainEater View Post
Tj Max is the temperature the cpu will throttle at.It is an internal on die temp.

The thermal specification is the maximum external case temperature.

Now obviously , these are very different things.Typically Tj max is about 20-30 degrees higher than the thermal specification.

There is debate about the whole maximum temperature issue , but here's the only thing you need to know : Operating your CPU above the thermal specification voids the warantee.

Here's some more reading on it :

The Truth about Temperatures and Voltages - Overclock.net - Overclocking.net

You're right, you shouldn't run the CPU above the thermal spec. However, the real question is how to tell whether or not you are doing that, and here's the simple answer: you can't. Intel has a very specific method of measuring Tcase (the temperature used as a reference for the thermal spec), which involves placing a certain type of thermocouple into a channel in the heatspreader and monitoring the surface temperature of the CPU at the geometric center of the packaging. Obviously this is impossible for the average person to do (not to mention the fact that it would DEFINITELY void the warranty), so you can take any hope you have of getting a temperature you can reference to the Tspec and toss it out the window.

The only temperature readings that are halfway reliable are the ones that come from the DTSes built into the CPUs, which are actually intended for a completely different purpose than the thermal spec. They are calibrated for use with the built-in thermal protection features; they read in terms of distance to Tjmax - a value which is set in the factory - and when that distance is equal to 0, the PROCHOT signal is sent which triggers the CPU's thermal throttling feature. The problem with these sensors is that although they are the closest we can get to a real measurement of core temperatures, they are calibrated specifically to be accurate only at and near Tjmax, and the farther away from that you get, the more of an error you have in the readings. So unless you're within 10-20C of Tjmax, the reading you see can vary by as much as 10-15C in the moderate temperature ranges, and significantly more than that when we start getting into the region most CPUs sit at when they are idle.

So what's the endgame with all of this mess? The fact is that temperatures are not something you have to worry about with Intel CPUs, period. Either the CPU is running in the safe range (below Tjmax, which is "around" 100C for current Intel CPUs - the "around" 100C thing is yet another mess), or it isn't, in which case your cooling is inadequate. Unless you're doing extreme overclocking and are using sub-ambient cooling, every degree doesn't really matter, and so long as your chip is sitting in a comfortable temperature zone, you don't have to worry about getting it cooled down any more. My rule of thumb is to leave at least 10C to Tjmax, just so you don't have to worry about any random temperature spikes tripping the thermal throttling (not because it's bad for the CPU, but because it will reduce your performance; you don't have to worry about doing anything bad to the CPU as far as temperatures go). If you really want to be paranoid, leave 15-20C. But more than that, you don't have to worry about a thing. Intel designs their CPUs to be very robust, and they are also designed so that under normal ambient temperature conditions, it is absolutely impossible for a non-defective CPU to suffer any heat-related damage.


Last edited by Zero82z; March 9, 2010 at 11:38 AM.
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  #29 (permalink)  
Old March 9, 2010, 02:21 PM
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Originally Posted by Zero82z View Post

You're right, you shouldn't run the CPU above the thermal spec. However, the real question is how to tell whether or not you are doing that.
Yep.

Generally I measure mine with a thermometer , but not everybody can do that so we're stuck with all the Tjmax BS.

I do also use hardware monitor.

If I go more than 6 c above the thermal spec on my e6600 ( as measured with HW mon) it starts erroring out on folding , and thats what were talking about here.

------

Like I said , there's a lot of debate about the issue.

My original advice stands. 75 C is too hot .get a better heatsink.

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  #30 (permalink)  
Old March 9, 2010, 03:00 PM
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Quote:
Originally Posted by BrainEater View Post
Generally I measure mine with a thermometer , but not everybody can do that so we're stuck with all the Tjmax BS.

I do also use hardware monitor.
No offence, but your thermometer is even more useless than distance to Tjmax readings. Hardware Monitor also provides readings based on distance to Tjmax, as well as a CPU reading which actually comes from a motherboard sensor, so again, useless (starting to sound like a broken record here).
Quote:
Originally Posted by BrainEater View Post
If I go more than 6 c above the thermal spec on my e6600 ( as measured with HW mon) it starts erroring out on folding , and thats what were talking about here.
I've taken my Q9550 much higher than that while folding, and I've never had a problem. I've run an overclocked Q6600 at comparable temps as well and not had any folding errors. I'm quite certain the problem you were having was caused by something other than just temperature.
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Originally Posted by BrainEater View Post
My original advice stands. 75 C is too hot .get a better heatsink.
No, not really. 75C is not too hot at all.
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