why does CPUs/CPU cores seem to be capped at 3 – 4 Ghz since almost a decade?
In: 1368
Not a ELI5. But aside from heat issue, digital design makes certain assumptions.
Two assumptions that I can think of start to break down at higher frequency. (1) Assumption about the wire transmitting the signals being short relative to the wavelength. As you go to higher frequency, the wavelength becomes shorter and this assumption starts to breaks down. (2) There are electromigration requirements. As you go higher frequency, the wires conduct more current on average and they break down faster. In theory you can make the wire wider to support the additional current but the logic gates that digital designers use usually favor being compact rather than supporting large current. Thus they cannot go too fast.
Chips or sub-components inside chips that go higher than 5GHz exist. But they are designed by people with different skill set. Usually they are called analog mixed signals (AMS) engineer or radio frequency (RF) engineer, depending on the speed and applications they are targeting.
Latest Answers