Why are the GHz speeds in computers the same after such a long period of time?
In: Engineering
For something to oscillate past a few GHz, the length of time between two signals has to be short. That time is now *not long enough* to cross the entire length of the silicon chip. This means that one signal can “overtake” the one in front of it, which causes absolute confusion and merry hell as we design chips to be “synchronous” (i.e. things happen at the same time everywhere).
We don’t have asynchronous chips (we can have multiple chips that aren’t in sync, but one chip tends to have a single concept of “a clock signal” that turns on and off regularly and makes everything else happen).
Past about 5GHz, the length of the pulses needed for that clock signal mean that, even at the speed of light, they can’t make it across the physical length of the silicon chip before another one starts its journey.
Making the chips asynchronous, shorter, or quicker actually makes things incredibly complex and liable to all kinds of problems if there’s a bug found later on. Not to mention, the higher the clock speed, the more heat given out (because the power required to make more oscillations is greater), which means more cooling or more problems with heat, and more interference.
Pretty much, we’ve hit a physical boundary that you can only compensate for by making chips tinier and tinier (which has other problems, not least manufacturing), colder and colder (supercomputers are sometimes liquid-helium cooled or similar), or more and more complex to design, produce, run, program and diagnose.
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