4 ms·

Can someone help me understand around what time did performance per watt become more important than performance per dollar?

czzr 6y ago
2007
stagger87 6y ago
Both have always been important in different contexts.
blihp 6y ago
It started with the Pentium 4. The tradeoff of power/heat for the increased clock speed stopped paying off. In fairness, Apple/IBM/Motorola also learned this lesson with the G5 but they were minor players in the market and were largely ignored. So it was roughly between 2005 and 2008 when perf/watt became a thing. I think public awareness of it had a lot to do with Steve Jobs relentlessly pushing perf/watt to help explain the PPC to Intel transition as Apple was just starting its public awareness rocket ride thanks to the iPod taking off.
agumonkey 6y ago
laptops
RantyDave 6y ago
I'd say somewhere in the 2005 ballpark. Performance per watt matters for mobile, obviously, but also for "hyperscalers". If you plug a chip in and run it at full tilt for five years, the cost of the electricity eclipses the cost of the chip quite handily.
ksec 6y ago
Around Pentium 4 and Centrino, so somewhere around 2002 - 2003 ish. The initial projection was that Intel could scale their transistor down indefinitely, we could somehow cool Pentium 4 effectively, and management think clock speed sells, so some day they could scale to 10Ghz CPU. That was when they hit the TDP ceiling. Internally named as Thermal Wall by Intel CTO Patrick Gelsinger. Before Pentium 4 Intel saw the rise of Laptop computer where energy efficiency was the key. And Pentium-M was a side project from (cough) Patrick Gelsinger. Which ultimately saved Intel's Pentium 4 fiasco. The market might have unlimited Dollar for performance. But it is still limited by TDP.
- maerF0x0 6y ago
  With work from home/covid lockdown I am more and more interested in going back to a desktop computer (vs macbook pro). In a desktop performance per watt effectively doesn't matter. Similarly with the chromebook as a portal to servers/cloud resources too (eg run your IDE in a cloud instance or something) ... I wonder if performance per dollar will ever come back ?
  - ksec 6y ago
    >In a desktop performance per watt effectively doesn't matter. Unfortunately it does. Just different sort of ways. If you want 64 Core, And you have max ~250W TDP CPU on a computer ( Assuming no fancy cooling ). You are effectively limited to less than 4W per core. Even less if you exclude memory controllers and Interconnect. You could argue you want 32 Core or even 16 Core, but scaling the up the clock speed curve beyond optimal level will means power increase exponentially. i.e You are still hitting the same wall. And I should note, with anything per dollar, the question isn't really technical per se, but function of market. AMD is pretty good at performance per dollar right now, and will be more so once they announce Zen 3. Some day if I could be bothered I should write a blog post on it.

czzr 6y ago

2007

stagger87 6y ago

Both have always been important in different contexts.

blihp 6y ago

It started with the Pentium 4. The tradeoff of power/heat for the increased clock speed stopped paying off. In fairness, Apple/IBM/Motorola also learned this lesson with the G5 but they were minor players in the market and were largely ignored. So it was roughly between 2005 and 2008 when perf/watt became a thing. I think public awareness of it had a lot to do with Steve Jobs relentlessly pushing perf/watt to help explain the PPC to Intel transition as Apple was just starting its public awareness rocket ride thanks to the iPod taking off.

agumonkey 6y ago

laptops

RantyDave 6y ago

I'd say somewhere in the 2005 ballpark. Performance per watt matters for mobile, obviously, but also for "hyperscalers". If you plug a chip in and run it at full tilt for five years, the cost of the electricity eclipses the cost of the chip quite handily.

ksec 6y ago

Around Pentium 4 and Centrino, so somewhere around 2002 - 2003 ish. The initial projection was that Intel could scale their transistor down indefinitely, we could somehow cool Pentium 4 effectively, and management think clock speed sells, so some day they could scale to 10Ghz CPU. That was when they hit the TDP ceiling. Internally named as Thermal Wall by Intel CTO Patrick Gelsinger. Before Pentium 4 Intel saw the rise of Laptop computer where energy efficiency was the key. And Pentium-M was a side project from (cough) Patrick Gelsinger. Which ultimately saved Intel's Pentium 4 fiasco. The market might have unlimited Dollar for performance. But it is still limited by TDP.

maerF0x0 6y ago
With work from home/covid lockdown I am more and more interested in going back to a desktop computer (vs macbook pro). In a desktop performance per watt effectively doesn't matter. Similarly with the chromebook as a portal to servers/cloud resources too (eg run your IDE in a cloud instance or something) ... I wonder if performance per dollar will ever come back ?
- ksec 6y ago
  >In a desktop performance per watt effectively doesn't matter. Unfortunately it does. Just different sort of ways. If you want 64 Core, And you have max ~250W TDP CPU on a computer ( Assuming no fancy cooling ). You are effectively limited to less than 4W per core. Even less if you exclude memory controllers and Interconnect. You could argue you want 32 Core or even 16 Core, but scaling the up the clock speed curve beyond optimal level will means power increase exponentially. i.e You are still hitting the same wall. And I should note, with anything per dollar, the question isn't really technical per se, but function of market. AMD is pretty good at performance per dollar right now, and will be more so once they announce Zen 3. Some day if I could be bothered I should write a blog post on it.