– Why does clock speed matter on a CPU, and why do some top-tier CPU’s have lower clock speeds than some from nearly 10 generations ago?

Question

I have a good understanding of what clock speed is, but why does it matter?

For the second question, I was wondering since for example, the new i9-14900K has a base clock speed of 3.2 GHz, whereas my previous desktop CPU, the i7-4790K, had a base clock speed of 4.0 GHz. Why hasn’t this number steadily gone up thought the years?

In: Technology

Answer 1

Okay, doing my best to honor the name of the subreddit.

Okay, you’ve got a Honda Civic. Doesn’t carry a lot and doesn’t go very fast, so it takes a long time to move a given number of packages from city A to city B. with a whole bunch of trips back and forth.

Then you buy a Tacoma, which also doesn’t go too fast, but can carry a whole lot more, so you can increase the number of packages you can deliver in a given time. Many fewer trips back and forth to deliver all your packages.

Then you go all out and buy a Ford Raptor. It increases your payload a bit further, but you can also drive that sucker 120 mph, so you can deliver even more packages a lot faster. Multiple trips from A to B seem to happen in the blink of an eye!

Then you change up technologies and find out that a long haul semi truck may only go 75mph, but it can handle so much more per trip that it is night and day faster at delivering a lot of packages, even though its speed is actually much slower. Even though it is slower, but cutting down your number of necessary trips from say 100 down to 20, it is still a huge improvement over the faster Ford Raptor.

Then you change up further and discover how much more you can move with a freight train than a semi truck, even though the pure speed is yet one level slower, down to 50-60mph. Even though it is slower, it only now takes one trip from A to B to deliver even more packages.

Hopefully that makes sense to your five year old self! 😉

The more instructions you can process and the more data you can move in a single clock tick, means you can potentially get more done with a slower clock than a simpler computer that does less per clock tick but with a faster clock.