Im waiting for that answer too. Seems we have to rewrite the laws of physics soon.
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It doesnt "go" anywhere. It stays within the circuit. The heat that people are seeing is mostly related to electromigration, ie current jumping from more than one level/circuit of the chip which causes resistance and that resistance is turned into heat
That is why i7s are not too bad at lower frequencies but get RED hot at higher ones. Its the same thing that got Netburst into trouble a couple years ago
You didnt answer the question. You simply sprew out jibberish.
And electromigration would result in radiation and material degeneration. It would actually reduce heat. Electromigration ionizes and physically moves particles out of circuits. Hence lost of kinetic energy instead of heat. And then learn the law of conservation of energy.
The power cant stay within the circuit. You keep on pumping power in. A CPU is not some battery you can charge.Quote:
In physics, the law of conservation of energy states that the total amount of energy in an isolated system remains constant. A consequence of this law is that energy cannot be created or destroyed. The only thing that can happen with energy in an isolated system is that it can change form, that is to say for instance kinetic energy can become thermal energy. Another consequence of this law is that perpetual motion machines can only work if they deliver no energy to their surroundings, and that devices that produce more energy than is put into them are impossible.
In short. SOI aint above the law.
Yes, i7 are hot chips, no doubt about it. There are people reporting that all over the dman web, so there's really no point in trying to convince people otherwise. I doubt they're hot enough to burn a house down, but then again, look what happened with Xbox 360!
OK lets get this clear:
100W = 100W, Voltage = Voltage
Yes, if you pump in 100W in any resistor the energy must go somewhere => heat, make it easy and say 100W heat.
Explanation why Deneb might run cooler then Nehalem:
Power formula is: W=(U^2)/R
But what most people seem the forget is that Power is also U*I. And that Resistance is not constant.
The Resistance in Nehalem surely differs from Deneb. But they also draw different amount of ampere.
I don't know the voltage figures for Nehalem but its less then Deneb 1.35V i hear.
So its very wrong to think that I and R are same for both processors and blindly look at voltages and draw the conclusion that Nehalem is cooler by default.
So in an example: W=U*I.
Deneb: 1.35V*80A = 108W
Nehalem: 1.2V* 100A = 120W
Deneb is cooler in this example.
An other example, same voltages: W=(U^2)/R. R=constant=1ohm.
(1.35^2)/1 = 1.82W
(1.20^2)/1 = 1.44W
Nehalem is cooler in this example.
A CPU cannot just absorb electricity and keep it in the circuit. Almost every bit of electricity a CPU uses must be converted to heat, because they do not any kind of physical work. A CPU is basically a giant resistive heater.
If a CPU doesn't draw a lot of power, but get hot, and heats up real quick under an increased heat load (ie. overclocking), then that points to an issue that the die surface physically can't remove heat fast enough from the transistors (like the old Athlon Thoroughbred A vs B), or the heatspreader or TIM is of a sub-par material not able to transfer heat well enough.
If a CPU has a high power draw, but stays relatively cool, then it points to the die being able to remove heat faster from the transistors, having a better TIM and heatspreader material.
Or the most likely cause for both: Software temperature readings of the CPU are complete crap and worthless.
http://www.xbitlabs.com/images/cpu/i...dale/pcons.png
http://www.xbitlabs.com/images/cpu/i...le/pcons-2.png
Its all about the sensors ;)
Quote:
As we have expected, CPUs on 45nm core are overall cooler than their predecessors on Core micro-architecture. However, the temperature different under 100% workload makes only 4-5 degrees. The thing is that Wolfdale processor core is smaller and features higher transistor density within a semiconductor die, which makes it a little harder for the heat flow to dissipate properly. That is why Wolfdale and Conroe heat up almost identically in idle mode. As for the relatively low temperature of AMD Athlon 64 X2 6400+, with twice as high TDP as that of Core 2 Duo actually, it can be explained by the not very best location of the on-die thermal sensor that is situated quite far from the hottest spots of the processor’s semiconductor die.
That is not what I said and yes I did anwser your question. The heat is generated by resistance. Resistance which SOI helps to alleviate now if you want to go on about how nice Intel is, fine. i7 is a great CPU no one disputes that but SOI does reduce TDP go look it up if you dont believe me.
Actually, ya they were. Not everyone lives in Denmark
By that arguement either all the money AMD and Intel spent on SOI was worthless or whomever packages Intel's processors needs to be fired because of the dozens cpus I have owned of both AMD and Intel chips and by far since AMD went SOI their chips have been noticablly cooler running.
As to Shintai's chart there is no way that info can be correct as the Intel chips are less than half of their rated TDP with AMD 2x above their. Bias? I think so.
No you didn't. You said some crap about the power stays in the circuit. If you USE LESS power you PUT OUT LESS heat. If you have a CPU that uses more power then another, then it also puts out more heat. If it runs cooler according to its ondie sensor, that means the sensor is not near the hottest part of the core, or the heat transferring abilities of the chip is better. SOI does not magically make heat disappear.
@Eson, HOW are they noticeably cooler running!? Have you milled a channel right into the IHS of both AMD and Intel CPUs, put a thermocouple in it, and used the exact same cooling solution on both CPUs, with the exact same ambient, while comparing power using of the CPU directly with a calibrated power meter? Or are you talking about what temp coretemp gave you, without paying attention to the actual power the CPU draws? SOI reduces power usage, which in turn reduces heat output. If a non-soi CPU draws less power then an SOI CPU, the SOI CPU is GOING to put more heat. That is fact.
Anyone who trusts software readings of a CPU to have any kind of accuracy is a fool.
I guess the good results wit 45nm node are more due to Immersion Lithography technology along with overall well constructed process rather than the SOI.
SOI helps to decrease the power draw of the circuit, that is e.g:
Bulk 130W
SOI: 105W
(It does not mean that 130W SOI would generate less heat than 130W Bulk would!)
The only way to determine how "hot" a chip runs is to measure the wattage it draws from the motherboard. More watts translates to more heat.
If the practical max. power draw of PhII is 80W and the TDP is 125W(meaning that the stock cooler is rated for handling loads up to 125W), I'd understand how the PhII indeed "runs cool" - due to good stock cooler and "low" power draw.
It all sums to the power the CPU draws from the motherboard. If it draws 125W then it will run hot no matter what. If it will draw less, then it really might run cool.
Just a reminder: TDP rating is for cooler manufacturers mostly and does not really have anything to do with actual power draw of the chip - other than the fact that usually the power draw is more or less near the TDP.
Thats something which caught my eyes since i know that C2D uses DTS to measure the temps, with Ci7 it even more interesstening, since there are far more DTS then they where in C2D. Does PII still relay on the Analouge probes to measure the temp?
I cant find anything about that, but if they use another method you really cant compare PII and C2D or Ci7 tempreature wise.
If i go with the sensore that says cpu the temp is somewhere ~ 57°C (Core temps are ~74°C under full load crunching wcg/seti with 8 threads :) )
yeah 3.4 at idle and only 25 watts at load that's why the 775 bioard have 12 phase power on the board then and digital too. >_>...
lol phases mean jack:banana::banana::banana::banana:... most of that is marketing... why do you thing the smackover only has 6 phases, hell msi even only has 5. :p
All that phase madness was a e-peen contest between gigabyte and asus who got the most phases. :ROTF:
thats to reduce ripple and help stablility how much different is 6 vs 16 is anyone's guess
its like 4 times oversampling vs 16 times oversampling back in the early CD player days
That is correct ... Don't forget the cosinus of the phase change between the Voltage and the Amps ...
Most of the people think that doing Amps x Volts is enough to figurout the watts, it is actually not accurate, CPU can be inductive or capacitive. :up:
The rest of the thread is "voodoo" science ... :)
I propose to add the age of the bus driver in the equation ... lol !
Core i7 was optimized to give you the best performance for its TDP. It, by design used as much head room as it can gets. You will see that to get to the level of performance of Core i7 965, you ll need to overclock the Phenom II over 5Ghz ... look at the power of the Phenom II then ...
I am not even talking to the idle power of the Phenom II, I think you ll get a surprise on who is the hotter chip.
Inside its TDP, Core i7 is unbeatable, it was design for this. Using 130Watts is what it was design for. Try to beat it in 130Watts with any other CPU.
No one is talking about performance, we're talking about power used and heat generated. Personally I don't give a :banana::banana::banana::banana: what the Core i7 965 is capable of, I just want a CPU that can clock decently and not perform a Chernobyl in my neighbourhood.
As soon as the i7 965 isn't a $1000+ chip and can work in socket 775 (just as PHII works backwards...) I'll be impressed. :shocked:
Until then it's another new platform to upgrade to and another chip you get the privilege of paying an extra $500 to unlock the multiplier.