So this is probably really stupid, but why, for a company such as AMD, cant they make a CPU similar to the 3970x but with 8 or so big cores with improved performance? I keep seeing insane core counts from them, but I don’t quite get why they can’t make really good single-core performance.
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Bigger is not better for CPU cores. Think of a CPU core as an engine that will always output the same amount of power regardless of its size (More on this in a bit). But the bigger it is, the more heat it generates. To prevent it from melting itself, we need to cool it. You cool it by either sticking something on it to suck away the heat or by slowing it down. Smaller CPU produces less heat which means it can run faster for longer.
Now on the (counter) intuitive nature of bigger does not equal more power. A CPU is a logic circuit. Which means when you send electricity in a certain pattern through it, it will send electricity out in a certain pattern. Power for a CPU is determined by how quickly it will send that pattern out. Suddenly doubling the number of transistors in the CPU core is not going to make it spit out that pattern any faster. It depends on how quickly electricity can get in and out of the core, not the number of transistors it goes trough to do it.
So why have we been shoving more cores into CPUs? Well, the chip is going to be a certain size. Transistors have been shrinking in size for as long as they have existed and they can fit more transistors onto the chip. We’ve long passed the time where we really need to add more transistors to the CPU core to make it faster. So the next best thing to do with all that extra chip space is to shove more cores in there (Technically cache space helps but that’s another story).
You’ve mentioned stuff like TurboBoost that Intel has. Well, in that scenario Intel does a clever trick because their CPU is limited by heat. The CPU itself can actually go really fast (This applies to AMD as well), much faster than their quoted specs. But the problem is that running it at that speed will basically melt the CPU. So they shut down unneeded cores which now no longer produce heat. That means the one running core can now crank up its speed because it can produce more heat by itself before melting the whole CPU.
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