Aanvullling op tdp verhaal:
Intel has traditionally specified processor power with a specification called Thermal Design Power (TDP).
AMD also has a TDP specification. Recently, AMD has introduced an additional power value called ACP (Average CPU Power). As of this writing, ACP is only specified on AMD’s server processors.
Intel defines TDP as follows: The upper point of the thermal profile consists of the Thermal Design Power (TDP) and the associated Tcase value. Thermal Design Power (TDP) should be used for processor thermal solution design targets. TDP is not the maximum power that the processor can dissipate. TDP is measured at maximum TCASE.1.
AMD Opteron* processors also have a TDP specification. According to AMD documentation2 their TDP specification is as follows:
“TDP. Thermal Design Power. The thermal design power is the maximum power a processor can draw for a thermally significant period while running commercially useful software. The constraining
conditions for TDP are specified in the notes in the thermal and power tables.
AMD probeert juist TDP naar ACP te krijgen.
AMD TDP shows the worst case power draw a particular chip can experience when it's operating at max voltage.
A chip can easily draw a lot of power, but usually only for very short periods of times (like several microseconds). If enough power isn't provided, bits and bobs get lost along the way and calculation errors start cropping up, which is really bad news. So, one would need to be able to supply that much power to the CPU at any given moment, even though CPUs can't draw max current for extended periods – even, say , 1/1000th of a second – making it all very difficult. Over 1/1000th of a second, the CPU could draw between 75-150 watts, but average power usage might be 110W.
When a firm is designing heat sinks, it only really cares about those longer periods of time, while people interested in the actual power, really care about every microsecond.
Intel has a spec for the maximum power of a CPU, it also has TDP, for its heat sink/cooling guys to worry about and adds a thermal diode to shut down the CPU if it starts overheating.
AMD, which only recently began using thermal diodes, has had to be more conservative in designing heat sinks, because the chip could actually overheat. Thus, the firm has had to keep its TDP more conservative than Intel's, hence the reason AMD would rather not talk about it and use a different metric.
Samengevat: Bij Intel zijn eventuele pieken in stroomverbruik (van 1/1000e van een seconde) niet relevant omdat er een diode in de cpu zit gebakken die de cpu beschermt. AMD had die luxe niet en zijn daarom dus al jaren anders aan het meten. Zoals in de quote genoemd geeft Intel (ivm voeding) de maximum stroomafnamne apart aan.
De genoemde 3870K is overigens best wel een zuipschuit zie:
Crank up the processor, though, and AMD's four cores consume significantly more power than Intel's two. With both a graphics and host processor load applied, the results are similar.
Overclocking doesn't do AMD's solution any favors. A combination of higher voltage and elevated clock rates push system power consumption up significantly at idle, yes. But the 100+ W jump under a mixed graphics/processing load is particularly disappointing.
In theorie leuk voor all purpose (niet voor gaming, zie ook bovenstaande link) alleen dan zou ik zelf voor de zuinigere cpu kiezen.
edit: Punt was dus dat het "niet halen" niet te maken heeft met het al dan niet gelijktijdig volladen van de cpu en gpu, maar met de definitie die AMD er op na houdt. Verder gewoon informatief
[Reactie gewijzigd door sdk1985 op 9 december 2013 21:58]