system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are the GHz speeds in computers the same after such a long period of time?
gpt
Rather than increasing processor speed, which is becoming increasingly difficult thanks to things like substrate bleed (which is a whole other conversation), the push hasn't been to increase clock speed (measured in Hz) but rather to simply add more processor cores. As software development has matured and proper utilization of multiple cores to get work done has become commonplace, the value of number of cores has steadily outpaced raw clock speed. 

Clock speed used to be king because there was only a single "pipeline" at work in the processor. Stuff went in at one end, did what it had to do, and came out the other end. The faster you could get through the pipeline, the better. Modern processor architecture has added more and more pipelines running together. By spreading what's coming in across multiple pipelines, it keeps everything flowing more smoothly than trying to stuff it all through one pipeline. 

Additional factors include decreasing cost and size of what's called *cache memory*. This is memory that's actually on the processor itself and is used to store data the processor is actively using. It's far, far faster than having to write data to system memory and retrieve it. Between increased cache memory and more effective use of multiple processor cores, the importance of raw clock speed has sharply dropped off over the past 10 years.