Itโs the age-old PC gamerโs dilemma: You have one of the best graphics cards on the market, but the rest of your system is showing its age, so should you upgrade your CPU or not?
It might not come as a surprise that the answer is โit dependsโ.
While a CPU upgrade doesnโt usually have as great a gaming performance impact as a GPU upgrade does, itโs not unnoticeable. Besides, thereโs more than gaming to considerโ your CPU is the brain of your entire computer, after all.
To decide whether to upgrade, you need to figure out exactly what you want out of a CPU, and you need to know whether your current CPU is still up to the task in modern games and applications.
What does the CPU do?
The CPU (central processing unit) is like the brain of the computer. It computes all the instructions that are given to it by your operating system and programs, although it does delegate some tasks to other components.
Modern CPUs have multiple โcoresโ, which can be thought of as individual CPUs in their own right, which perform operations simultaneously. CPUs also run at a certain โspeedโ, measured in MHz (megahertz) or GHz (gigahertz), often โboostingโ up to higher speeds when needed.
CPU vs GPU for gaming
Because your CPU is what runs all the instructions given to it by your operating system and applications, it affects every aspect of your desktop experience arguably more than any other component. As an upgrade to the โbrainโ of the computer, a CPU upgrade should improve all aspects of your desktop experience, not just gaming.
A GPU (general processing unit), however, only works on things like graphics rendering, which makes having a powerful one important for specific things like gaming and animation software but less important for most general-use apps. For these specific use cases, though, a graphics card upgrade should give you a much bigger performance uplift than a CPU upgrade.
Deciding whether to upgrade your CPU or GPU largely comes down to how important you find gaming or using render-heavy applications. If you want to increase your in-game FPS, a GPU upgrade will likely be the better choice. But if you want to improve your day-to-day desktop and app performance, you might be better opting for a CPU upgrade.
CPU Cores for Gaming
Games have always been much more reliant on a CPUโs single-core performance than its multi-core performance. Single-core performance refers to how fast your CPUโs individual cores can compute instructions, whereas multi-core performance is how fast your CPU performs operations that utilise multiple cores.
This has started to change over recent years, but not dramatically so. Older games shouldnโt need more than four cores to run optimally, but newer games have started utilising six cores very well, which means having a six-core CPU should make the most of todayโs games. Having more than six cores is usually overkill if gaming is your primary concern, though.
On the other hand, if you see yourself undertaking heavy productivity tasks like video editing, the more cores your CPU has the better.
CPU Speed for Gaming
Because a CPUโs single-core performance is still more important than its multi-core performance for gaming, its speed is often more important than its core count.
A CPUโs clock speed is measured in MHz (megahertz) or GHz (gigahertz), which measures how many โcyclesโ of transistor toggling your CPU can execute per second. The more cycles per second, the more calculations it can perform each second.
But a CPUโs overall speed doesnโt just come down to its clock speed, because how the CPU is designed can also affect how many instructions it can complete each second. For this reason, the number of instructions per clock (IPC) that a CPU can perform is also important.
Regardless, itโs difficult to know how quickly a CPU will perform different tasks without actually seeing it perform these tasks, which is why itโs best to look at real-world benchmarks and reviews to see whether a CPU is worth purchasing.
How to Check CPU Performance
So, you know what to look for in a CPU, but to decide whether to upgrade you also need to know how this compares to your current CPUโs performance. The best way to do this is to run CPU benchmarks and CPU-intensive games and compare your results to CPU benchmarks online.
But you might also want to know whether your CPU is holding your system back by bottlenecking your other components, because if this is the case then youโll know you need to upgrade without having to compare it to other CPUs at all.
What is a CPU Bottleneck?
โBottleneckingโ refers to when one component is capping your PCโs performance and the rest of the system would be capable of performing better if this one component were upgraded. A CPU bottleneck is when your CPU is acting like the neck of a bottle, preventing the rest of your systemโs power potential, the metaphorical liquid in the bottle, from pouring out quickly and being realised.
For instance, if you have a great graphics card but a weak CPU, your CPU might not feed data to the graphics card as fast as it could theoretically handle. In this case, your graphics card wouldnโt be being used to its full potential because the CPU would be artificially capping its performance.
If your CPU is bottlenecking your system in this way, it might be time for an upgrade.
How to Test for a CPU Bottleneck
To test for a CPU bottleneck, you need to find out how much of your CPU is being utilised while running apps and games and compare this to your GPUโs utilisation.
To check for a bottleneck, itโs better to run games that you play and apps that you use rather than running CPU benchmarks and stress tests. CPU benchmarks and stress tests often try to max out your CPUโs load, meaning theyโll always show close to 100% CPU utilisation.
By running games and apps that you use, you get a more accurate picture of your CPUโs day-to-day utilisation and whether itโs bottlenecking your system. If your CPU is at, or just below, 100% utilisation while playing games, and if your GPU isnโt close to maxing out on utilisation, then you know that it is likely bottlenecking the rest of your system while gaming.
To check your CPUโs utilisation, you can use a program like HWMonitor, which should show all your CPU coresโ utilisation percentages in a separate sub-section.
If you donโt have HWMonitor downloaded, however, you can use Windows Task Manager to monitor your CPUโs utilisation.
Press Ctrl + Shift + Esc to open Task Manager, navigate to the โPerformanceโ tab, then select CPU. You should now see a graph showing your CPUโs utilisation percentage. Right-click the graph, hover over โchange graph toโ, and select โlogical processorsโ. This should show the utilisation of all your CPUโs cores and threads.
Now, boot up some of the most CPU-intensive games you own and see what those graphs look like while playing. This is my CPU utilisation while playing the Overwatch 2 beta:
One thing to note is that having one or two cores close to 100% utilisation is not uncommon and is only a problem if your CPU doesnโt have many more CPU cores than this. And while itโs useful to look at individual core performances, you should also keep your eye on your CPUโs total utilisation percentage underneath the graphs.
It should be obvious if your CPU is bottlenecking the rest of your system. Youโll notice that your GPU utilisation (on the left-hand side of Task Managerโs Performance window) isnโt close to maxing out, while your CPU utilisation is maxing out on most of its cores. Given that most modern games utilise about six cores, if six or more cores are at max utilisation when you play games, then you likely have a CPU bottleneck.
When Should you Upgrade your CPU?
If your CPU is bottlenecking your GPU or other components, you should consider upgrading. You should monitor your CPU and GPU utilisation while gaming in Windows Task Manager to check this.
Your CPU will likely be bottlenecking other components while gaming if it has less than six cores, given that most games utilise six cores these days. However, for some games four cores is still sufficient.
You should consider more than just gaming, though. If you use CPU-intensive applications, such as for professional editing, then itโs usually worth upgrading your CPU every two or three CPU generations. Similarly, if youโre running a very old CPU you might want to upgrade just to improve your day-to-day desktop experience.
You should also consider whether you need the latest technologies associated with a CPU upgrade. For example, if you want the latest PCIe and DDR standard capabilities youโll need a modern motherboard and CPU combo.
A good rule of thumb, however, is that if you have a current- or previous-gen Intel or AMD CPU with six cores or more, upgrading your CPU likely wonโt give you a big gaming performance uplift. If your CPU is a few generations old or has less than six cores, however, and if you already have a good graphics card, then upgrading your CPU should give you a noticeable performance boost.