As many of you may know, Cities: Skylines is a CPU intensive game, meaning that a good processor plays a key role in performance. RAM is also an important factor, however for this guide I will just be covering CPUs.

I am creating this guide to help people choose a CPU if they want to play Cities: Skylines on their computer. There are many misconceptions that I have seen in regards to the CPU and their performance in Skylines, so this guide will address them.

DISCLAIMER: Mods can skew results. Therefore, your results may vary if you are using different mods, especially CPU heavy ones. For the purpose of compatiblity, this guide will be based around an “overall perspective.” If you are looking for mods that may have a negative impact on performance, check out this discussion posted by RottenDub:
https://steamcommunity.com/app/255710/discussions/0/1692659135915855227/

Last updated: June 3, 2021

The Basics

To start off, Cities: Skylines is mainly single-core dependent due to the limitations of the Unity engine being used for the game. This means that a CPU with strong single-core performance will give you better performance in the game.

It is also worth noting that Cities: Skylines was originally optimized for 4 core/8 thread processors, meaning that anything at or above that level is ideal.

Two factors that determine a CPU’s single-core performance are IPC and clock speed.

Clock speed

A CPU’s clock speed is a metric used to determine how many clock cycles the processor can conduct per second. For example, a CPU with a clock speed of 3 GHz can conduct 3 billion cycles per second. Each “gigahertz” represents 1 billion cycles.

IPC

The other factor that determines single-core performance is IPC, or instructions per clock. As the name suggests, this is a way to measure how many instructions a CPU can execute, per clock cycle. The IPC of a CPU is dependent on a processor’s architecture.

To find the single core performance of a CPU, multiply the clock speed by the IPC.

A Common Misconception

Clock speed can ONLY be compared between two CPUs if their archiecture is the same. I often see people claim that CPU 1 is better than CPU 2 in Cities: Skylines because it has a higher clock speed, yet both CPUs have a different architecture (eg. Intel Comet Lake vs Intel Rocket Lake, or even Intel vs AMD.) This is wrong, because as stated earlier clock speeds can only be compared if the CPUs are from the same architecture. The only way to reliably see which CPU has the best single-core performance is by running benchmarks like Cinebench R20 Single-Core. These benchmarks take into account a CPU’s clock speed and IPC.

To put clock speed and IPC into perspective, think of two CPUs that both run at 50 MHz. CPU 1 has an IPC of 1, while CPU 2 has an IPC of 1.5. Look how quickly CPU 1 can overtake CPU 2 just by having a higher IPC:

1 cycle:
CPU 1: 1.5 instructions
CPU 2: 1 instructions
2 cycles:
CPU 1: 3 instructions
CPU 2: 2 instructions
10. cycles:
CPU 1: 150 instructions
CPU 2: 100 instructions

Since Cities: Skylines is single-core dependent, it is important to look for an architecture that has a high IPC. From there, look for a CPU that has a high clock speed within that architecture.

Skylines can also benefit from more threads, as that is how AI parts of the game such as pathfiding, water simulation, etc. are calculated. Most of the time, any CPU with more than 8 threads should be fine.

Recommendations

Now that IPC + clock speed and how they impact performance have been covered, here are some recommendations for CPUs that may be worth considering if you are building/buying a computer for Cities: Skylines.

At the time of writing this, Intel’s Rocket Lake and AMD’s Vermeer (Zen 3) architectures have the highest single core performance, however Intel’s Comet Lake CPUs offer the best value. If you are playing Cities: Skylines only, I recommend a Rocket Lake or Zen 3 CPU. If you are playing other games, however, consider looking at Comet Lake as they have a good value.

That being said, here are some of my recommendations:

Best four-core CPUs

Intel Core i3-10100:
This four-core CPU scores around 430 points on the Cinebench R20 Single-Core benchmark test. While it may not be the best performing CPU here, it is one of the least expensive CPUs at the time of writing this.

AMD Ryzen 3 3100/3300x:
I have not seen both of these CPUs in stock for a couple of months now. However, in the event that you do happen to have one, the Ryzen 3 3100 has the same single-core score as the i3-10100 at about 430-440 points, depending on which reviewer you look at. The Ryzen 3 3300x has better single-core performance at around 490-500 points.

Best six-core CPUs

Intel Core i5-10400 and Intel Core i5-10600K:
These two Intel Comet Lake CPUs have Cinebench R20 single-core scores that are roughly tied with the i3-10100, R3-3100, and R3-3300x at 430 and 490 points respectively. However, the only reason I am including the i5-10600K here is because it is overclockable, which can be helpful to improve performance further. If you are not overclocking, consider getting the i5-11400 over the i5-10600K (see below).

Intel Core i5-11400 and Intel Core i5-11600K:
Both of these CPUs scored pretty high on the Cinebench R20 Single-Core benchmark. The i5-11400 scores around 540 points, and the i5-11600K scores 600 points. That said, the i5-11400 is still very respectable as it beats all previous generation i5s, and is tied with the Intel Core i9-10900K.

AMD Ryzen 5 5600x:
Scores 600 points on Cinebench R20 as well, tying it with the i5-11600K.

Best eight-core CPUs

Intel Core i7-10700/F/K/KF:
Like the i5-10600K, it has a lower score in Cinebench at 500-510 points, but at the time of writing this it is less expensive than other 8-core CPUs. It also has similar gaming performance to the Ryzen 7 5800x in games besides Skylines.

AMD Ryzen 7 5800x:
Scores 620 points on Cinebench R20, placing it right at the top of current CPUs.

Ten cores, twelve cores, and beyond

I usually don’t recommend purchasing CPUs that have more than 8 cores if playing Cities: Skylines or games in general, as it will become diminished results. However, if you need/want one:

Intel Core i9-10850K/10900K:
Has a respectable single core score on Cinebench with 540-550 points, which is around the score of an i5-11400 (again, a fast six-core CPU like the 11400 can have just as good single-core performance despite having lower clock speed, due to a better IPC).

Ryzen 9 5900x and Ryzen 9 5950x:
AMD’s flagship CPUs with 12 and 16 cores. Both have around 620 points, similar to the Ryzen 7 5800x.

Final Thoughts

Cities: Skylines is in my opinion one of the best city building/simulator games out there, but unfortunately it doesn’t mean that the game has hardware limitations, the CPU being one of them.

Intel’s Alder Lake desktop processors will release near the end of 2021, and they are set to have a substancial single core performance increase over Rocket Lake. I strongly recommend checking out hardware channels on platforms like YouTube such as Linus Tech Tips or Hardware Unboxed for the most up-to-date information on specs, pricing, and performance, and looking at single-core benchmarks.

Hopefully this guide was helpful for making a decision on which CPU to buy. There are, of course, a bunch of other factors that can also affect performance, but the CPU is arguably one of the most important ones that determine performance in Cities: Skylines.

A huge thanks to Aubergine18 and Enter Plasma for making their PC component guides. Please check them out, as they cover other parts that can impact/improve performance.

If you have any questions or suggestions for this guide, please let me know in the comments below 🙂

This is all about Cities: Skylines – CPU Guide (and other hardware information); I hope you enjoy reading the Guide! If you feel like we should add more information or we forget/mistake, please let us know via commenting below, and thanks! See you soon!