• monocasa 5 hours ago

    This is the Dennard of Dennard Scaling, a chip scaling law that is arguably as important as Moore's Law.

    https://en.wikipedia.org/wiki/Dennard_scaling

    The end of Dennard scaling was why the Pentium 4 architecture was a dead end and never hit 10Ghz like it was supposed to, why the Cell processor never hit the 5Ghz it was supposed to, why we've been spending quite a bit of the transistor budget on more cores rather than a very fancy single CPU core of 10Bs of transistors, and why chips with lower thermal limits will see a lot of "dead silicon" where you can't actually light up the whole chip at once without melting it.

    • pclmulqdq 4 hours ago

      Dennard scaling, for people in the industry, was far more important than Moore's law when it was available.

      Moore made a high-level observation, but Dennard told you how to do it.

      • mepian 4 hours ago

        >The end of Dennard scaling was why the Pentium 4 architecture was a dead end and never hit 10Ghz like it was supposed to, why the Cell processor never hit the 5Ghz it was supposed to

        Around that time the PowerPC 970 aka G5 also failed to achieve 3 GHz, breaking the promise Steve Jobs publicly made at one of his keynotes for Apple.

        • martinpw 2 hours ago

          > The end of Dennard scaling was why the Pentium 4 architecture was a dead end and never hit 10Ghz like it was supposed to

          I've always been puzzled by this. Did Intel really not see this coming? I remember talking to Intel engineers way back when they were promising 10GHz in the near future - I think the codename at the time was Tejas. They seemed very confident. The architecture must have already been planned out - and yet it seems from the outside like the end of Dennard scaling was a total surprise to them?

          • throwup238 an hour ago

            Intel (and almost everyone else tbh) didn’t fully appreciate how Denard scaling would play out at smaller nodes. They expected to keep lowering the transistor threshold voltage alongside transistor size but that became increasingly difficult due to leakage currents.

          • cpldcpu 4 hours ago

            Well, it's basically the technical implementation of Moore's law, since Moore's law is just an empirical observation. (And maybe also a self-fulfilling prophecy)

            • senkora 2 hours ago

              Now there will be a twinge of sadness whenever I read a paper beginning with “Since the end of Dennard scaling…”.

            • declan_roberts 5 hours ago

              > 91

              I really hope I live as long as these guys. It's one thing to invent something useful, it's another to spend your life watching it grow.

              • adharmad 5 hours ago

                Roger Penrose is 93 and as sharp as a tack!

                • mhh__ 2 hours ago

                  Another: Ed Thorpe is similarly old and still going strong, last time I saw.

                  • declan_roberts 25 minutes ago

                    Built different.

              • scrlk 4 hours ago

                RIP.

                I was surprised that it didn't get much attention on HN when the news broke back in April, considering Dennard's large contributions to technology.

                • osnium123 5 hours ago

                  He passed away months ago. RIP. He seems like a class act from what I’ve heard.

                  • drzzhan 23 minutes ago

                    RIP.

                    • blisterpeanuts an hour ago

                      Bob Dennard enjoyed Scottish country dancing, which is how I knew him. He was a kind and humble man. R.I.P.

                      • gjvc 3 hours ago

                        (April)