Intel's recent launch of the Core i9-9900K has a lot of people asking what it means to have the best gaming CPU around. The answer to that question is complicated, and we wanted to take a break from our usual System Guide format to dive deep into this specific topic.
Let's start from square one. For one's CPU choice to influence gaming performance at all, a game has to be bottlenecked by the CPU to begin with. That may sound obvious, but not every game is CPU-bound. In fact, we'd guess that most aren't. We have to dig deep into our Steam libraries for titles that care much about the CPU they run on when we're getting set up for CPU reviews.
Older games like Grand Theft Auto V form the foundation of any CPU gaming benchmarking suite. GTA V is typical of many older titles in that it cares a lot about a CPU's single-threaded performance. You can easily find modern games that strongly care about the performance of a single thread, however, as Far Cry 5 seems to.
Developers' use of next-generation APIs in newer titles isn't a reliable predictor of CPU usage patterns, though. Gears of War 4's implementation of the DirectX 12 API is as dependent on a single core as ever when frame rates start to climb. Sections of Rise of the Tomb Raider can hammer every core at high enough frame rates, but that only holds true with the game's DirectX 12 renderer. RoTTR sequel Shadow of the Tomb Raider, on the other hand, doesn't seem to stress CPUs much at all in DirectX 12 mode.
Crysis 3, a favorite of ours for exploring the performance potential of CPUs for gaming, can stress every single thread one can throw at it despite the fact that it predated DirectX 12. The same is true of Assassin's Creed Origins and Assassin's Creed Odyssey, both of which use DirectX 11 and still occupy every thread we can throw at them (although the gap between the lowest- and highest-performance CPUs in those titles often isn't nearly as wide as it is with Crysis 3).
Even within the same game, API options can entirely change how a given title might stress a system. The Vulkan renderer in Doom's 2016 reboot doesn't max out any single core, for example, but its OpenGL renderer proves a great test of per-core performance, if nothing else. (Run Doom with Vulkan if you can, please.)
Point is, there's no easy way to make a general statement about how games will load a CPU short of hands-on testing and liberal use of Windows' Resource Monitor. Even if we can't predict how every game will behave, we know from experience that as frame rates climb and resolution, image quality, or both decrease, the CPU becomes more and more likely to be the bottleneck for a system's gaming performance.
Going by experience, we also know games that tend to end up CPU-bound usually end up stuck on a single thread. It follows that a game's performance ceiling can only be lifted by using a high-performance CPU with the highest possible single-core clock speed (or equivalent all-core overclock) one can throw at it. Titles that occupy the entire CPU stand to benefit from an all-core overclock, too. More speedy cores and threads lift all boats in those unusual cases.
To crown a gaming CPU as "the best," then, we want high single-threaded performance out of the box. We also want the highest all-core clock speeds we can get to handle the odd game that's embarrassingly parallel, and we want plenty of overclocking potential if we can get it.
How to choose a gaming PC's CPU
With all that in mind, picking the "best gaming CPU" for a given build is going to depend on how you want to play games. Do you have a 4K monitor and a hunger for today's latest titles with their settings cranked? In our experience, your CPU won't have a noticeable impact on frame rates. 4K gaming puts an insane load on your graphics card, and frame rates will probably stay in relatively pedestrian ranges unless you're doing something crazy like pairing GeForce RTX 2080 Tis in SLI.
For a 4K gaming PC, then, your CPU choice should depend on what else you do with your system. If you don't need lots of cores and threads for your day-to-day work, you can save some money on the CPU and put that cash into a more capable graphics card. We wouldn't take that approach to extremes, though: pairing a $100 CPU with a $1200 graphics card would be a bit silly.
CPU choice can matter some when gaming at 2560x1440, although the performance differences between chips aren't going to be nearly as keenly felt as they would be at the extremes of 1920x1080 gaming unless you have a GeForce RTX 2080 Ti. As always, the more powerful your graphics card is and the higher you want to push frame rates, the more likely it is that you'll notice a differences between CPUs when gaming at this resolution. Still, we'd allocate as much money to a powerful graphics card as possible for the best 2560x1440 gaming experience. Your CPU choice should still mostly depend on what else you want to do with your PC.
At the opposite extreme, do you play esports titles at the lowest possible resolution and highest possible frame rates? You'll want to pick a CPU with fewer cores and threads and higher per-core clock speeds—possibly one that's unlocked for easy overclocking. As you lower your game's resolution or image quality settings to the minimum to increase frame rates, you may find that you ultimately hit a point where frame rates will go no higher, and higher CPU clock speeds via overclocking may be the only thing that will push that FPS counter up any more.
The above advice holds true for budget gamers running titles at 1920x1080 with a graphics card like a GTX 1050 Ti, GTX 1060 3 GB, or RX 570, even if those gamers aren't pushing their systems quite to the same extremes. All of those graphics cards can be had for reasonable prices again these days, and they're quite powerful compared to what modest budgets used to buy. Upgrading to the midrange GTX 1060 6 GB or RX 580 will only increase the likelihood of CPU bottlenecks at 1920x1080. To get the most out of those graphics cards, you can't pick the slowest, cheapest processor available—you need a balanced system, and that might mean spending more than $100 on a CPU.
If you have a lower-resolution monitor, if you simply can't afford more than a certain amount of money for a CPU, or if you only have the budget to upgrade your graphics card in an older system, not all is lost. You can shift some of a game's load back onto the GPU by increasing image quality settings (anti-aliasing, especially), by using AMD's Virtual Super Resolution or Nvidia's Dynamic Super Resolution, or by enabling a combination of those things. The point is to exploit the untapped power of your graphics card to improve the gaming experience in ways unrelated to higher frame rates.
If higher frame rates are ultimately what you want in CPU-bound games—or your CPU is just so ancient that modern graphics cards are bottlenecking it, period—you're ultimately going to have to shell out for more processing power. We can help.