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
Clock speed is hard to increase and takes a lot of extra wattage for each additional Ghz.
For CPU performance we have Single Threaded performance and Multithreaded performance.
There are essentially 3 or 4 factors for CPU performance. Clock speed (this would be analogous to an engine’s RPM), How many cores the CPU has (not every workload scales with more cores), The IPC or Instructions Per Clock (which would be analogous to an engine’s torque) – this is how much “work” is done per “clock” (so a 4Ghz CPU with higher IPC will outperform a 4Ghz CPU with less), and Cache, which is the memory in the CPU (how much and how fast the cache is) – Although some would argue that cache is really a contributing factor to IPC.
For something like Intel 14th gen, they list the TDP (PL1) as 125W. So you’ll notice that the 14700K has a higher base clock than the 14900K (which has 4 more cores) – that is because the base clocks you’re seeing is what both CPUs will give you at the 125W rated TDP (of course these CPUs can boost past this 125W, which is your boost clock ratings). A 14900K for example can boost a core to 6Ghz.
To increase CPU performance, you can either increase IPC, increase cache, increase clock speed (all improve single threaded performance) or add more cores (strictly increases multi-core performance).
A new architecture is required to improve IPC. Intel (from 6th – 10th gen), for example, had the same fundamental architecture and IPC. They increased performance by adding more cores and clockspeed because their next architecture was delayed.
Your 14900K at 3.2Ghz is going to be faster than a 4790K at 4Ghz due to more IPC, more cache, and more cores.
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