# Do you think we will finally see a 35W APU only laptop when AMD Raven Ridge launches?

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## Do you think we will finally see a 35W APU only laptop when AMD Raven Ridge launches?

• ### No

• Total voters
24

#### amd6502

##### Senior member
Shivansps said:
maths that are related to dissipated temperature...
[...]
The amount of power converted to heat by a CPU is always as close to 100% as makes no difference.
He means heat, not temperature. A difference in temperature is associated with a quantity of heat that is dissipated.

Yes Shivansps, almost the sole product of the electrical energy that a processor takes is simply heat. There is a bit of blackbody radiation mostly around the infra-red that's radiated from the package due to its temperature, and there's a tiny bit of radio frequency radiation also from the acceleration of electrons, as they cruise around the sillycone ( https://en.wikipedia.org/wiki/Bremsstrahlung ). Information itself has zero joules of energy content, so perf/watt does not figure into the calculation of how much doesn't become heat.

TDP ratings are kind a bracket that gives you a ballpark idea of how much the processor may dissipate when it's under load. A processor or APU can exceed the TDP, but as the package heats up and exceeds some temperature ~65C and/or time limit, the APU will cut down frequencies of the CPU and GPU in order bring down the average power consumption back down to or under the TDP limit. Assuming the GPU isn't in use, this almost always means an eventual transition from boost or all core boost to base clocks.

So TDP doesn't even mean maximum power.

And as Abwx points out above, it's a bracket, so it's also quite possible that the maximum power could be well under the TDP rating. (Eg. a product that failed to make the 65W tdp cutoff would get assigned the next higher TDP rating, 95W).

Because of all of these variations TDP ratings vary from manufacturer to manufacturer, but essentially they give you a decent rough idea of the power consumed at load.

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