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by yrro 1259 days ago
What is the purpose of even providing a figure if it's not accurate?

(Maybe I'm wrong, I thought the TDP figure is the maximum sustained power that has to be dissipated by the cooling setup, the CPU can output more heat briefly but over a long period of time it'll average 65 W assuming it's fully utilized?)

3 comments

It's made up but does provide rough tiers within a product generation.

Also, modern CPUs and GPUs pretty effectively throttle to the capacity of their cooling solution. I would not necessarily recommend it, but you could probably get by without any issue slapping a solution that reliably dissipates 65W of heat on any Ryzen, and have a stable computer. It would just happen to run up to its thermal limit regularly and clock down.

If you actually want a lower power/heat setup, you can undervolt and underclock the CPU and not worry about bouncing off the thermal limits.

Sure, I should have included *without causing throttling etc. Things have come a long way in the 18 years(!) since this video was created...

https://www.youtube.com/watch?v=Xf0VuRG7MN4

Marketing. It's the same reason AMD decided to tier the Ryzen lineup into a 3, 5, 7, and 9.

Intel had products with TDP of 65w and 125w, so AMD "matched" that by making up a TDP formula to get the results they wanted. At the time, Intel's TDP was actually mostly accurate. It would turbo above that, but only for a few seconds before dropping to the TDP limit.

Then when AMD started winning, Intel had to get match them in return. If AMD's "125w TDP" parts could turbo forever, then why shouldn't Intel's? And so that's what they did. And just like that over a few generations TDP became entirely stupid & without a shred of meaning.

That's backwards really. The control loop works in the other direction by monitoring the temperature inside the CPU. The CPU will draw as much or as little power as the cooling system permits, as long as the demand exists.