A CPU consists of cores, and each core will receive and process instructions sent by the RAM. The more cores you have, the faster your CPU theoretically should be.
But there’s another way you can make a CPU faster, you can increase how fast an individual core processes information, this is what we call ‘single-core’ performance.
Increasing the single-core performance of a processor is extremely beneficial, especially if you’re a gamer, this is because multiple cores have little impact on how well MOST games operate.
Why Single Core Performance Is Important
Single core performance is crucial for most video games, and other applications that aren’t easily parallelized, this is because they can only use a single thread, so only benefit from a single core.
This is why you will see many gamers purchasing high clock speed processors as clock speed is just one aspect of single-core performance.
As you can see from the benchmark above, the processors with the higher clock speeds are usually the ones producing the most FPS.
For example, the I9 12900K is displaying the highest FPS relative to other 12th gen processors because it has the highest clock speed; the same applies to the Ryzen 9 5900X and the 5000th generation processors.
When considering clock speeds, it’s important to compare processors of similar generation and architecture, this means comparing 12th gen processors with only 12th gen CPUs. The same thing applies to Ryzen 5000 CPUs.
| CPU | Clock Speed |
| Intel Core I9-12900K | 3.20GHz(base), 5.20GHz(boost) |
| Intel Core I7-12700K | 3.60GHz(base), 5.00GHz(boost) |
| Intel Core I5-12600K | 3.70GHz(base), 4.90GHz(boost) |
| Ryzen 9 5900X | 3.70GHz(base), 4.80GHz(boost) |
| Ryzen 7 5800X | 3.80GHz(base), 4.70GHz(boost) |
| Ryzen 5 5600X | 3.70GHz(base), 4.60GHz(boost) |
This is to keep the playing field fair as it removes any performance difference that the CPUs architecture may include. This performance difference is also known as IPC.
What Constitutes Single Core Performance
With single-core performance, there’s two metrics you need to pay attention to, that’s clock speed, and IPC. So you must consider both of these metrics to get an understanding on a CPU’s single-core performance.
The clock speed defines how many times the CPU core cycles per second, and it’s measured in GHz(billion times per second).
The IPC defines how much work your processor can do per clock cycle, this is why IPC stands for (Instructions per cycle). The more instructions your CPU can complete per cycle, the faster it is single core wise.
Despite the clock speed of the CPU being marketed more, it’s actually misleading to only consider it, this is because some older processors will have high clock speeds, this doesn’t mean they can compare to newer CPUs of similar speeds.
This is evident when comparing the 12th gen Intel processors with the 10th gen Intel processors. The I9 12900K has a boost clock speed of 5.20GHz, whereas the I9 10900K has a boost clock speed of 5.30GHz.
The I9 12900K is still able to outperform it in every way including single-core performance, let’s take a look at some PassMark scores to get a better idea.
| Processor | Clock Speed | PassMark Single-Thread |
|---|---|---|
| I9 12900K | 5.20GHz(boost) | 4,375 |
| I7 12700K | 5.00GHz(boost) | 3,974 |
| I5 12600K | 4.90GHz(boost) | 3,973 |
| I9 10900K | 5.30GHz(boost) | 3,165 |
| I7 10700K | 5.10GHz(boost) | 3,072 |
| I5 10600K | 4.80GHz(boost) | 2,636 |
As you can see, the newer 12th gen chips outperform the 10th gen chips by an average of 518 points despite having mostly lower boost clock speeds.
But this doesn’t mean the older chips are bad in any way, you could probably find a great deal on some 10th generation chips, and they’re still plenty viable.
So single core performance is a product of both clock speed and IPC working together.
External Factors Can Affect Single Core Performance
The main external factor that affects single-core performance would be temperature. The temperature of your CPU dictates whether your CPU should thermal throttle or not.
Thermal throttling occurs when your CPU reaches a certain temperature, typically around 85-90C, and this causes your CPU to automatically underclock making it slower.
When your CPU thermal throttles, it’s mainly due to you not having sufficient cooling in place, you may need to purchase a better CPU Cooler to get better performance out of your processor.
Another single-core external factor would have to be RAM/Memory bottlenecks. Your CPU has to wait for your RAM to send instructions to the processor.
So, when your RAM doesn’t have enough bandwidth, or the capacity is too low, your CPU will have to wait an extended period of time before it can complete any tasks. This is an indirect effect on single-core performance.
Overclocking Can Improve Single Core Performance
When you overclock your processor, you are pushing your cores clock speed to work faster than they are designed to.
This is a great way to get more performance out of your processor without having to upgrade your PC.
So, if your processor has a clock speed of 4.9GHz, you should be able to push it to 5.0GHz if your processor is unlocked/overclockable.
An unlocked processor should have the ‘K’ suffix if you’re looking at Intel processors, and AMD CPUs are mostly unlocked by default.
To overclock your processor, you usually need to go into the BIOS to modify the clock speed modifier, it’s recommended to do this slowly to prevent damage to the CPU.
By slowly increasing the clock speed modifier, it allows you to find the upper limit of your CPU before it becomes unstable.
Once your CPU becomes unstable, you can choose to stop there, or you can try to increase the voltage to maintain core stability.
Increasing the voltage when overclocking is what has the potential to decrease the lifespan of your processor, so do this at your own risk.
How Is It Different From Multicore Performance
Multicore performance is pretty different from single-core performance, because it looks at how all the cores work in conjunction.
Your processor will have a set number of cores, for example, the Ryzen 5 5600X has 6 processing cores. The more cores you have, the more performance you get multicore wise.
Multicore performance is great for many types of applications such as X264 Software encoding, Video editing, and multitasking.
Unfortunately, having many cores doesn’t directly translate into higher frames per second in most games due to them being single-thread optimized.
What About SMT/Hyperthreading
Core count isn’t all there is to single-core performance, there is what we call SMT or simultaneous multithreading.
This can improve multicore performance by up to 30% in some cases, but it’s mostly application dependent.
When it comes to threads, when you purchase a processor, it should display the thread count next to the core count such as 6 cores, 12threads.
Most of the time, you will have double the number of threads than cores, so an octa-core processor with SMT capabilities should have around 16 threads.
When we talk about threads, they’re pretty much virtual cores, and they work by utilizing what we call “stalling”.
So, when one thread is working on one set of instructions, another thread can work on a different set of instructions. This speeds up the overall performance of your processor.
Conclusion
In conclusion, single-core performance is the product of the CPU architecture and the processor clock speed.
CPU architecture improvements are usually present with newer CPUs, this improves the single-core performance without having to change the clock speeds.
