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Discussion Starter #1
I wrote a simple C++ program to find out how many watts of power an overclocked cpu produces.

It is based on this formula

Quote:


OC Wattage = TDP * ( OC MHz / Stock MHz) * ( OC Vcore / Stock Vcore )^2

The text "^2" means "squared".

This formula is fairly self-evident. The stock/OC MHz is just how fast the processor is meant to run, and how fast you are in fact running it. Same with the vcore, which to any new people is the voltage that is run through the processor. Higher voltage means more stability, but also can lead to much higher power consumption, and if excessive, and early demise.

The only term that needs explanation is the TDP, or Thermal Design Power. The TDP is meant to be the wattage of the processor at load. I say "wattage" because it is unclear if this is meant to corrospond most immediately to how much power is consumed in watts, or how much heat is produced in watts, but as near as I can tell the TDP is pretty much meant to indicate both.

To get your processor's TDP, you must depend on AMD or Intel's own figures. In the case of AMD's XP line both maximum and typical are listed, and typical is what you want. Maximum is apparently if every single transistor were powered at the same time, which will never happen. Typical is meant to be the realistic maximum wattage.

source

here is the program and source code if anyone wants to see it. Its an easy program, but my math is kind of wierd at some points in the program so feel free to make suggestions. Attachment 33782
 

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Hey Buddy, Thanks I just down loaded and tried it...Very Nice...
....
 

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Discussion Starter #5
Quote:


Originally Posted by Burn
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...Java...


Mine comes out to 102.44W- Does that sound right?

depends it should be right but you could do it out by hand to make sure it works
I know I checked the prgram using sdumpers numbers for his conroe and it worked so.

Edit: whats your overclock and vcore?
 

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I did it through my calculator- The equation seems right, I cross-checked it on another site's CPU wattage calculator, same spec.
 

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Discussion Starter #7
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Originally Posted by Burn
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I did it through my calculator- The equation seems right, I cross-checked it on another site's CPU wattage calculator, same spec.

ok good some of the math is a bit messed up as I said. It comes out with the right answer just some of the steps to get to it are odd.
 

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Nice program however it is not very accurate. The problem is, the voltage you set in BIOS never reaches your CPU. This is caused by Vdroop. Also, your formula will not produce an accurate value because:

A. The TPD is not the amount of heat that a C2D puts out, however, it is the amount of heat the cooler is expected to dispell. The C2D may really put out 40 watts or even less.
B. The processors Mhz has no correlation to heat output, as far as I am aware.

Now if you could measure the Amps and voltage going to the CPU, you could calculate CPU wattage.
 

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Discussion Starter #10
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Originally Posted by pauldovi
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Nice program however it is not very accurate. The problem is, the voltage you set in BIOS never reaches your CPU. This is caused by Vdroop. Also, your formula will not produce an accurate value because:

A. The TPD is not the amount of heat that a C2D puts out, however, it is the amount of heat the cooler is expected to dispell. The C2D may really put out 40 watts or even less.
B. The processors Mhz has no correlation to heat output, as far as I am aware.

Now if you could measure the Amps and voltage going to the CPU, you could calculate CPU wattage.

The program may not be extremely accurate, but it isn't bad for approximations.

A. TDP represents the maximum amount of heat the cooling solution is expected to dissipate(as you said). The figure is high by default from the manufacture because the processor will never reach that heat level? So I guess the program doesn't calculate the total amount of heat, but maybe just how much the heatsink will have to dissipate in order to keep the chip in an acceptable temp range.

B. Raising the clock speed of a chip will increase its thermal output even if there is no increase in the voltage. I have seen an explanation for it but at the moment I can't find one
.

Thanks for the input


~jrs
 

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Hmm... so supposedly my CPU is drawing/pumping out 157 watts of heat. I'm surprised my little Arctic freezer 64 can keep it at 48C.
 

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Discussion Starter #12
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Originally Posted by Fishie36 View Post
Hmm... so supposedly my CPU is drawing/pumping out 157 watts of heat. I'm surprised my little Arctic freezer 64 can keep it at 48C.
Unfortunately that number is much higher than what it is really going to put out. AMD's TDP of 89w represents a value that is way over the top, and is a power consumption level that will never be reached at stock. I'll pm burn and see what he used when he calculated his, because his number came out to be around 100w......which means he used something lower and more realistic.

~jrs
 

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This should give you an idea of CPU heat production:



From this thread. The results come from a test I was doing on flow rate vs. heat transfer. The Vcore was at 1.55V, which was intentional to produce more heat. Actual CPU Vcores will be lower, and thus heat production as well.
 

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Discussion Starter #15
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Originally Posted by Mootsfox View Post
Mine is about 4 watts less overclocked than stock!

Haha....I assume because you have your vcore set below 1.4v?
 

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Quote:

Originally Posted by pauldovi View Post
This should give you an idea of CPU heat production:

From this thread. The results come from a test I was doing on flow rate vs. heat transfer. The Vcore was at 1.55V, which was intentional to produce more heat. Actual CPU Vcores will be lower, and thus heat production as well.
What if you have air cooling?
 

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Quote:

Originally Posted by Fishie36 View Post
What if you have air cooling?
Clearly it doesn't do a good job of showing performance with air blocks. But it should show you how much heat the CPU is making.
 

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Quote:

Originally Posted by jrs View Post
Haha....I assume because you have your vcore set below 1.4v?
Yup! 220mhz increase, .1v decrease.
 
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