5 ms·

Yeah...ELI5, what are those additional transistors really doing here if no big performance gain in benchmark or application, but in fact they still grow exponen

by eva1984 11y ago

Yeah...ELI5, what are those additional transistors really doing here if no big performance gain in benchmark or application, but in fact they still grow exponentially until now?

alcari 11y ago
They're acting as cache, to hide the latency to your RAM. They're implementing increasingly niche instructions that speed up ever smaller sets of programs. They're mostly sitting idle, because power usage hasn't fallen at nearly the rate of increasing density, so switching them all at the same time is a great way to start a fire. A significant part of the exponential gains in the '90s and early 2000s was that clock speed kept increasing. That's been stagnant for years because of heat problems.
- lmm 11y ago
  It's worth saying what's really happening here is that no-one cares about the desktop. Heat is important for servers and mobile, and modern CPUs are designed for that with desktops as an afterthought. On a desktop the abandoned Pentium 4 architecture can clock up to 12GHz and will beat modern CPUs for at least some workloads.
  - john_reel 11y ago
    Really? Are there any benchmarks available?
wtallis 11y ago
Every consumer-grade CPU now comes bundled with a GPU whether you want it or not. You've also got some other special-purpose stuff that makes certain tasks vastly more power efficient when you use it and costs basically nothing if you don't (random number generator, AES engine, the GPU's video transcoder). Some components are moving from elsewhere on the motherboard onto the CPU; for some processors this even includes significant voltage regulation circuitry.
yvdriess 11y ago
(Here is my ELI5 attempt using the one-syllable G. Steele format, assuming you know what a transistor is ;) Transistors get warm when they work. We have so many of them now that we can not make all of them work at the same time. The CPU would just melt. The transistors that are useful all the time, work all the time. These days, the number of transistors that useful all the time stay the same with each new CPU. Transistors that are useful sometimes, but are really good at that thing, get turned off when they are not working. What has changed is that all extra transistors that are added are really good at a specific thing, like drawing or talking. This way, a CPU can keep getting new transistors that are useful some of the time, as long as they get turned off when they do not need to work.

by eva1984 11y ago

Yeah...ELI5, what are those additional transistors really doing here if no big performance gain in benchmark or application, but in fact they still grow exponentially until now?

alcari 11y ago

They're acting as cache, to hide the latency to your RAM. They're implementing increasingly niche instructions that speed up ever smaller sets of programs. They're mostly sitting idle, because power usage hasn't fallen at nearly the rate of increasing density, so switching them all at the same time is a great way to start a fire. A significant part of the exponential gains in the '90s and early 2000s was that clock speed kept increasing. That's been stagnant for years because of heat problems.

lmm 11y ago
It's worth saying what's really happening here is that no-one cares about the desktop. Heat is important for servers and mobile, and modern CPUs are designed for that with desktops as an afterthought. On a desktop the abandoned Pentium 4 architecture can clock up to 12GHz and will beat modern CPUs for at least some workloads.
- john_reel 11y ago
  Really? Are there any benchmarks available?

wtallis 11y ago

Every consumer-grade CPU now comes bundled with a GPU whether you want it or not. You've also got some other special-purpose stuff that makes certain tasks vastly more power efficient when you use it and costs basically nothing if you don't (random number generator, AES engine, the GPU's video transcoder). Some components are moving from elsewhere on the motherboard onto the CPU; for some processors this even includes significant voltage regulation circuitry.

yvdriess 11y ago

(Here is my ELI5 attempt using the one-syllable G. Steele format, assuming you know what a transistor is ;) Transistors get warm when they work. We have so many of them now that we can not make all of them work at the same time. The CPU would just melt. The transistors that are useful all the time, work all the time. These days, the number of transistors that useful all the time stay the same with each new CPU. Transistors that are useful sometimes, but are really good at that thing, get turned off when they are not working. What has changed is that all extra transistors that are added are really good at a specific thing, like drawing or talking. This way, a CPU can keep getting new transistors that are useful some of the time, as long as they get turned off when they do not need to work.