On Friday, 20 April 2018 06:09:03 UTC+1, wrote:

"For every decrease in CPU power consumption, there is
an equal and opposite increase in clock speeds."

I stopped all attempts at overclocking in the Pentium 2 days, but I grasp the concept. However, from what I have gleaned the processor speed is not the end of the world usually. In a PC for example the RAM is slower, the HD slower than that, and so on until we get to the speed of access to data sources, i.e. the internet.

OTOH the CPU does a lot more than the others. Sometimes cpu is the limiting factor, sometimes not. IMLE with clocking it did make a significant difference. I don't bother clocking now, but once it was a deal maker.

So conceivably couldn't they just not crank the clock to the max and save power and generate less heat ? Or do they already do that ?

that's done nearly all the time. It's one reason why most CPUs are clockable.

My laptops have a setting, performance, balanced and battery life. Is that possibly an indirect "underclocking" control ? If not, what is it ?

probably. It also affects HDD power down settings on HDD equipped laptops.

"Might be an IGBT FET. Very low Vce(sat) at
high currents. However, it's not zero, so there's still some heat
that needs to removed. "

The current should not be that high, all that current is cumulative right ? Seems like the main issue is charging and discharging the input capacitance. As such,lower clock speeds should be quite effective.

There's capacitance everywhere that gets charged & discharged each time it changes between 0 & 1. There's also that conduction overlap time when something changes state.

If they could get it down to the point where no heatsink is needed at all, wouldn't there be enough advantage in cost to justify a slightly lower clock speed ?

you need a huge speed reduction to go heatsinkless.

A phone accessing the internet for example, how much does that clock speed really mean then ? I am not being sarcastic here, that is a valid question, (I think) how processor intensive is all this ?

Modern net browsers are real cpu hogs


Maybe there is advertising value. I could see the yuppies in the cellphone store looking at specs and saying "LOOK, this one has a higher clock speed !".

Or are these the issues that keep the engineers up at night ?

As more & more gets squeezed into a cpu, power use per flop has to fall dramatically. There is no other way. The future lies with very low power gates relative to today.


NT