If computer clocks max out somewhere around 5GHz, how is it possible for 100Gbit internet to exist? How does the computer possibly transfer that much data per second?
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5GHz is what is today the top clock speed of the computer, but that do not mean you can’t make higher-frequency electronics. It also ot not mean that a single bit is processed per cycle. If you just use a regular 64 bits register and use one per cycle the CPU process 320 Gbit of data eacy cycle.
In a computer, there are many transistors that propagate to each clock cycle. So if you design electronics with fewer transistors the signal has to go through the frequency you can run the chip at an increase.
A single induction will be split up into multiple stages where one stage is done per cycle. the previous stage can be used by the next instruction the next cycle. So the same hardware can be reused every cycle and the same sized chip can do more, this is called https://en.wikipedia.org/wiki/Instruction_pipelining
How many steps you have to do depends on the design, Splting it up in more stages increases the clock frequency the chip can run at. The problem is making steps like that is not free, you need special electronics that store the output of one stage and send it to the next stage in the next cycle. So more and more of the worker is just this and less work is done in between. These parts also require extra transistors and use more energy.
The power usage is directly proportional to the frequency so if you increase it the power usage go up. Add to that the required extra part that uses more power. To make transistors switch faster you can increase the voltage and it increases power too.
No let’s go back ack over two decades to the https://en.wikipedia.org/wiki/Pentium_4 It use lots of stages and can manage a high clock frequency. They managed 3.6Ghz in a 65nm process back in 2006 and used 86 for a single-core CPU. The highest clock frequency varan operates at 3.8 GHz with a 90nm process in 2004
In 2006 Core 2 Duo E6600 was released. It runs at 2.4Ghz with two cores and uses 65W in the same 64nm process. but the performance per core was proximally double that of the Pentium 4 so with two cores it could reach 4x the performance with lower power usage. There were multiple reasons but a major one was it had fewer steps did more per cycle and wasted less power.
It is power and the heat of the CPU that is the major limitations today. You need to remove it all so they do not overheat. So the CPUs have a design that results in the frequency we see with multiple cores because that way you can do the most work for limited available cooling.
The transistor has shrunk to 4nm today so each switches faster and usel less power. The design has improved and do more each clock cycle. If you look at single-core benchmarks of a Core 2 Duo E6600 from 2006 and a i9-13900KS from 2023 the GeekBench 5 Single-Core was 324 vs 3093. The i9-13900KS has a tubo boos frequency of 5.8GHz which is 5.8/2.4= 2.4x the clock frequency. If we scale the result with the frequency we get 777 vs 3093 that is 4x difference
So in the last 17 years, a single core at the same frequency is 4x times faster. They spent the available power budget on more hardware that do stuff in parallel in a CPU not in a higher clock frequency because that is the new way to get high-performance
So there is nothing intrinsic that limits the electronics to 5GHz. If you need transceivers for communication interfaces you can build them in a way that allows a lot higher frequency. Because just receiving a single signal i not a lot of work you can have electronics that detect the amount of light in an optical fiber at a high enough range to detect 100 billion puls per second. It is only a single task not a lot of stuff at the same time like a CPU. The signal can then be split up in multiple parallel lines and the digital electronics that process it can run at a lot lower frequency.
100Gbit/s= 12.5Gbyte/s and if you can process 64 bits = 8 bytes at the time it you only need to do that 1.56 billion times per second. The CPUs we us have 64 bit registers. That is something a CPU can handle today.
The slowest DDR5 memory is DDR5-4000 (PC5-32000) it has 4,000 million transfers per second in a 64-bit wide bus. That is 256 Gigabit/second for a single DIMM and you have 2 channels for a standard consumer motherboard for a total of 512GBit/s. The faster memory DDR5 memory standard is at twice that but I do not know if it is implemented.
The slowest DDR4 memory is
DDR4-1600 and is 64-bit wide too. This means a single DIMM can handle 1600*64=102 Gbit/s of data. So if your computer use DRR4 memory the interface to it is over 100Gbit/s
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