KungFuHamster t1_j4215gy wrote
I thought smaller transistor sizes were supposed to require less power, not more?
5kyl3r t1_j42evo4 wrote
let's use a simple example
you have 4 LED that is fits in car headlight but only 4 fits because they're huge. it uses 80 watts total (20w each)
next year they release new LED's that are 20% more efficient and half the size, so 16w each. but since they're half the size, you can fit twice as many now. 8 led's * 16w = 128 watts total
this is what happens with cpu's. the size of the transistor shrinks, and so does power use of each transistor. but since they're smaller, the companies pack way more of them onto the processor. if you have enough, it can end up being more power. if they kept the transistor count the same, it would use less power
carl_on_line t1_j4226ty wrote
They do, but new chips have billions more transistors and switch them faster, that drives power consumption up again.
Avieshek OP t1_j42g0rr wrote
They do and hence why they've aimed and achieved beyond 5GHz on all cores but if they stop chasing after numbers for marketing purposes you'll likely see the efficiency improvements in power consumption like AMD or Apple (who barely hits 3.5GHz with their M1s) though also dial in the fact that they're not fabless and have their own fabrication standards in case of Intel so you can't compare with TSMC the customers of which others are.
StarsMine t1_j4293tb wrote
The following numbers are not correct for this node But when new nodes come out you get stats like 20% more performance at same power Or 80% power at same performance These numbers come directly from the fabricators and do not take into account at hectare changes.
What you are still allowed to do is do is Use 20% more power and get 1.5x the performance
rakehellion t1_j42ca1d wrote
More transistors and higher clocks require more power.
TheOGBombfish t1_j431w4m wrote
The actual formula for calculating switching energy is approximately E=C * Vdd^2 * fs, where C is the load capacitance (larger the transistor higher the C), Vdd is the operating voltage and fs is the switching frequency.
This means that increasing the frequency affects the power consumption at the same rate as decreasing the physical size of the transistor lowers it.
Ofc making transistors smalles is extremely difficult at the moment, which means that the increase in switching frequency pretty much negates it. This combined with the increased transistor count pretty much guarantees that higher performance -> higher power consumption.
red_vette t1_j42itzl wrote
Performance per watt goes up, but the increase in transistors far out paces it.
algernon132 t1_j426yyd wrote
Actual transistor sizes have hardly gone down in years now
oneplusetoipi t1_j42cw31 wrote
This is incorrect. It is not scaling like the name suggests but they are definitely getting measurably smaller.
https://www.tsmc.com/english/dedicatedFoundry/technology/logic/l_5nm
In fact, in order to “print” a transistor requires extreme UV light so that the wavelength is small enough that the fringing effects do not ruin the outline of the printed structure.
https://en.wikipedia.org/wiki/Extreme_ultraviolet_lithography
It is very expensive and requires a lot of maintenance.
The smallest patterning is used for the transistors and the lowest metal layers. The higher metal layers still use regular UV optical pattern printing.
throwaway1point1 t1_j42w8pq wrote
The size of the transistor has gone down, helping efficiency, heat, etc, allowing higher clocks.
But they can't put them much closer like previous node advances.
algernon132 t1_j42wq2p wrote
Gotcha, thank you. I mistook gate pitch for transistor size.
5kyl3r t1_j42f646 wrote
well we're down to what 2 nanometer now? a single atom is 0.1 - 0.5 nanometers, so we're nearly down to the size of individual atoms lol. not sure what'll happen after that
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