Just how many CPU cores do you need for PC gaming? The conventional wisdom for the last few years has been four or even two cores—if you have Hyper-Threading.
That convention got upended with DirectX 12’s ability to use multi-core CPUs more efficiently than previous DirectX versions. But how many more? I broke out the latest gaming benchmarks to find the answer.
How I tested
For my test I used the latest build of Windows 10 on a PC with an eight-core Core i7-5960X, 32GB of DDR4/2133 RAM, and an AMD Radeon Fury X GPU. To see the effect of losing cores, I manually switched off cores and Hyper-Threading while running the test.
Note that as you scale back the core count on the chip, Turbo Boost reacts by giving you a little more clock speed. Rather than turn off Turbo Boost, I’ll just note that up to two cores with Hyper-Threading, the chip runs at 3.5GHz. Beyond that it ran at 3.3GHz. In an ideal world, I'd use different CPUs, as each specific chip reacts a little differently, but this is a pretty reasonable approximation.
The first test I ran was Maxon’s Cinebench R15. It’s a great real-world benchmark that gives you an idea of how more threads could pay off. It doesn’t scale forever, as I discovered when testing the Falcon Northwest Tiki, but here with a “mere” eight cores, it climbs for the stars.
Cinebench R15’s rendering test, though, is a pure CPU test. What about gaming? For that, I first turned to 3DMark’s API overhead test. This was one of the first showcases for all that is possible with DirectX 12, and when I tested it last year I found that a quad-core with Hyper-Threading paid huge dividends over a dual-core. The chart below pretty much proves that cores matter more than clock speed.
You want to see eight cores in DX12?
Last year, unfortunately, I didn’t have an eight-core chip available and had to settle for quad-core numbers. This time, with an eight-core rig up and running, the results are far more interesting. 3DMark’s feature test shows DirectX 12 scales very nicely as you add Hyper-Threading and and core counts. Unfortunately, it hits a wall at about six cores. Adding Hyper-Threading and more cores made no difference.
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