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Topic Title: AMD's TDP Definition for Athlon 64 CPU's
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Created On: 10/25/2004 10:00 PM
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 10/25/2004 10:00 PM
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qlawson
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I know AMD refers to TDP as the maximum design specification for thermal output of a given CPU. But what is not made clear by their definition is if this value really applies to a family of CPU's (90nm Athlon 64's for example) as opposed to being a real indicator of a specific chip's (90nm Athlon 64 3500+ for example) maximum power consumption. Could someone clarify this, or point to some official documentation that answers this?
 10/25/2004 10:35 PM
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zir_blazer
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Maybe I can clarify some things... The Thermal Power Dissipations are usually for an entire specific line, and they are the Maximum Watts that a Processor that falls in that category can dissipate under Full Load condition. The 130 nm Athlons 64, for example, have a maximum Thermal Power Dissipation of 89 Watts, however, no Processor actually reach that amount. That is a security measure so Cooler manufacturers make they products to support at least 89 Watts of dissipation that makes that the Athlons 64 run in a safe temperature range. The Athlon 64 FX-55 is the only Processor that is in another range (Up to 105 Watts, but is nowhere close to that), while AMD claimed that the entire line of 90 nm Athlons 64 will dissipate only 67 Watts at Full Load. Hope than that helps
 10/26/2004 12:12 PM
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qlawson
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Thanks zir_blazer,

I agree with your explanation. This explanation seems to be the prevailing opinion from those "in the know." However, I have been unable to find any documentation or reference (official or unofficial) directly from AMD to confirm this. Do you know of any?
 10/26/2004 12:14 PM
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Greyhound
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Does this' ">http://www.amd.com/us-en/asset...nd_tech_docs/30430.pdf help ?

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AMD Athlon 64 X2 6000+ 89W :: Asus M2N32SLI Deluxe :: 2x1024MB Muskin XP2-6400 DDR2-800 :: BeQuiet! Darkpower Pro 530W :: 2x WD Raptor 74GB/10k rpm, RAID 0 :: ATI Radeon X1950XTX
 10/26/2004 12:52 PM
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ZapWizard
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The above linked sheet is great.

Also each CPU at time of release has a PDF with it's induvidual specs, including thermal.


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 10/26/2004 12:59 PM
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qlawson
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Thanks for the link Greyhound,

That PDF does show the TDP value for each processor. The problem is that the TDP value is the same for the entire 130nm Athlon 64 family (2800+ through 4000+) at 89 Watts, and for the existing family of 90nm Athlon 64's (3000+ through 3500+) at 67 Watts.

The best example to illustrate this problem is comparing the 130nm 2800+ (1.8GHz) with the 130nm 3800+ (2.4GHz). They both have a TDP value of 89 Watts. The only difference between the two parts is a 600MHz clock frequency (same voltage, same cache size, same die size, etc.). Conventional wisdom (and several independent tests) says that the 3800+ part must consume more watts. Therefor if the 3800+ part were to consume 89 Watts, the 2800+ part must consume less, so its TDP value can not be it's actual power consumption.

I can not find any AMD documentation that indicates *actual* maximum power consumption or that clarifies the disparity.
 10/26/2004 01:06 PM
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Greyhound
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AMD's TDP-values are usually absolute maximum(=worst case) values for an entire line of processors, i.e. 89W is the maximum TDP for ALL 130nm SOI Desktop Athlon 64s, regardless of model number.

In real life, your processors' actual power-dissipation usually won't get anywhere near these maximum values....of course, a 3700+ model will get closer to the max than a 3000+ model(assuming both are running at full speed and voltage, i.e. at high CPU-utilization or with Cool'n'Quiet disabled).

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The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates.

<center><font color=red>MODERATOR</center></font>

AMD Athlon 64 X2 6000+ 89W :: Asus M2N32SLI Deluxe :: 2x1024MB Muskin XP2-6400 DDR2-800 :: BeQuiet! Darkpower Pro 530W :: 2x WD Raptor 74GB/10k rpm, RAID 0 :: ATI Radeon X1950XTX
 10/26/2004 01:30 PM
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qlawson
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I agree with you Greyhound. Many have postulated this. My only problem is that I haven't been able to find any AMD documentation to confirm this. Even if it doesn't give actual maximum power consumption values, a basic agreement with the content of your previous post would work. For example, a 130nm Athlon 64 2800+ should *never* reach 89 Watts dissipation, assuming that it's running under recommended specifications (no overclock). But its TDP value wouldn't tell you that.
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