Differences: Core Duo vs Core 2 Duo

I was reading at both datasheets from Core Duo and Core 2 Duo.
I got the following:

Core Duo:
Voltage at highest frequency: from 1.1625 to 1.3
Voltage at Lowest Frequency: from 0.76 to 1.0

Core 2 Duo:
Voltage at highest frequency: from 1.03 to 1.3 (good, less voltage)
Voltage at lowest frequency: from 0.75 to 0.95 (good, less voltage!)

But, when I looked at Current (Icc), it shows the following:
Core Duo: T2600 (ex), 34A when on 2.16ghz
Core 2 Duo: T7400 (ex), 41A when on 2.16ghz

Core Duo: 15.5A when on 1ghz
Core 2 Duo: 27.3 when on 1ghz

That's a 7A difference between both processors at Highest Frequency mode and almost 12A difference when on lowest frequency mode.

That should be considered when upgrading a processor right, because, AFAIK, thermal heat dissipation is a product of voltage vs current. So, in an upgrade from CD to C2D, your heatsink would most probably have to deal with something like 9 to 12W more...

Right?

*PS* I'm still trying to understand this post:
http://www.thetechrepository.com/showthread.php?t=126

 

erm not sure about amps, but core duo tdp is 31W and core 2 duo is 35W or 25W. Even besides, this, you can undervolt those CPUs so it will use less power(except for the lowest multiplier), and overshadowing this issue is the fact that generally, if you have bought a laptop with a Core 2 Duo CPU, you wouldn't dream of swapping it with a Core Duo CPU (and generally you can't), and if you purchase a laptop with a Core Duo CPU, the graphics processor is going to be of an older generation and that's probably what you would care about more, and what would be a larger deciding factor if you care about battery life. Also, there are other components in a laptop that consume power as well such as the screen, hard drive, chipset, and when you purchase a laptop, you would purchase it for the whole package and not just a single part.

Simply, do you have a laptop with a Core Duo CPU that you've been thinking about upgrading to a Core 2 Duo CPU? The main reason for this would be that the Core 2 Duo CPU can run 64-bit operating systems, and the Core Duo cannot.

 

Core 2 Duo = completely new architecture
Core Duo = two Pentium Ms stapled together

There's your difference. C2Ds perform clock-for-clock better than C1Ds.

 

Well, I'm only questioning the TDP difference of 4W. The TDP calculation should be based on average use or something, because the specs are clear.

My point is: Core 2 Duo should generate much more heat than Core Duo.

 

Intel uses a terrible TDP calculation because it's not based on average use. I believe TDP is the maximum possible power draw from the CPU at stock specifications. At idle or average use, the Core 2 Duos are definitely more power efficient than the older Core Duos.

 

The A cannot represent Amps. I'm surprised those values are this high as a washing machine does not use more than 20A. Knowing that the t7400 TDP is 35w. The formula for power is P = I * V. And P = 35W, I = 41A at full speed. With I > P, V would need to be less than 1V. Either their value are wrong or they are lying about their TDP as the core voltage on Intel website for the T7400 is 1.1625V-1.300V which would put the current at ~26A when running full throttle...

 

Actually, it can and does use that much current. Power = Voltage x Current. If you look at PSU specs, for example, each 12V rail can support 20A and you can get PSUs w/ 3 12V rails to support a total of 60A. While this is for desktops, notebooks aren't much different.

 

Clock for clock, a Core 2 duo is 30% faster than a core duo.

In my testing, the T7x00 processors run cooler than the T5x00, which run cooler than the T2x00 processors. I have concluded that this is because of the die size of the processor. The T2x00 have the smallest die, and the T7x00 have the larger die size. Since there is more surface area to conduct heat, the T7x00 conduct heat better to the heatsink, thus running cooler.
At least that was the case in my E1505, where I had a T2500, T5300 and T7400. During all cpu tests, the processor was at 100% load and the fans were at 100%. To this day, my T7400 runs cooler than my T5300

His amps are right.
Example
My Opteron 185, uses 125 watts
It runs at 1.4V, so that is 89.3 amps at full power

The lowest voltage I can get on my socket M core 2 duo is 0.950V

K-TRON

 

Well, running cooler definitely could be related to the larger die, because it would transfer more heat from the die itself to the heatsink. But, the fact that in theory, Core 2 Duo Merom would use 1.3v and draw 41A when used at highest frequency represents that it would consume 41 x 1.3 = 53,3W?
P = I * V?

41A and 1.3v are on the Intel Core 2 Duo Merom datasheet...

 

You can't just throw numbers together. Just because those are the absolute max values doesn't mean that at max voltage, you use max current. The TDP of the CPU is the max power draw, irrespective of the individual voltages and current values supplies by the data sheet.

 

Why I can't?

Check this sentence from the datasheet (page 82)

"The TDP specification should be used to design the processor thermal solution. The TDP is not the maximum theoretical power the processor can generate"

Written by Intel (c)

 

Ok, let me rephrase. Don't take everything so literally with Intel's figures. According to Intel's power engineers, the TDP is a top end figure and in real life work loads, you will not be able to attain it. Most of the engineering specs are based off safety factors and while your theory of multiplying the two highest numbers is sound, it doesn't translate to how the CPU works (it won't draw that current at max voltage). Furthermore, as you quoted, Intel uses TDP as a measure of heat that needs to be dissipated and while related to power draw, it is not directly proportional.

If you want the most accurate results, find someone (like K-TRON) with a Kill-a-Watt to measure the power between the two processors.

http://www.silentpcreview.com/article169-page3.html