We don’t know whether Intel was listening to Taylor Swift when it created its all-5GHz Core i9-9900KS Special Edition chip, but maybe you know the line about Haters gonna hate, hate, hate, hate, hate. Because yes, haters, no matter what the reason was for the Core i9-9900KS SE to exist, we know you’re gonna hate.
After testing this unlocked CPU against its predecessor the Core i9-9900K and the Ryzen 9 3900X, both fine CPUs in their own right, the truth is, as always, more complex. The Special Edition’s all-core Turbo Boost indeed delivers impressive performance. But when you look at bang for buck, Ryzen 9 3900X still has a lot to offer. Read on for the details.

What is the Core i9-9900KS Special Edition?
Intel’s Core i9-9900KS Special Edition was first announced at Computex. The CPU is built on Intel’s mature 14nm++ process. It is, for all intents and purposes, the very best of the well known Core i9-9900K we reviewed.
While the 8-core Core i9-9900K had an official base clock of 3.6GHz and officially would push one or two two cores to 5GHz on Turbo Boost, the 8-core Core i9-9900KS Special Edition can push all eight cores to 5GHz.
Note the key words there: Turbo Boost. The Core i9-9900KS does not run full-time at 5GHz all day, every day. It just goes there an awful lot. This isn’t an easy feat to do as a product you can offer with a warranty. Yes, most of the original Core i9-9900K CPUs would run happily at 5GHz, but that was technically overclocking. The Core i9-9900KS Special Edition is sanctioned to do it and will do so automatically. Other than that, it is the same as the original Core i9-9900K.
It is essentially a “binned” or sorted chip, where Intel takes the very best of its Core i9’s and makes them into the Core i9-9900KS Special Editions. All for the low cost of about $25 over the $489 of a Core i9-9900K CPU. For those who must see them side by side, we’ve rounded up all of the 9900-series parts here on Intel’s ARK.
Because you’ve known about the CPU for months and read our review of the Core i9-9900K as well as our review of the Ryzen 9 3900X, let’s just get into the testing.
How we tested
For this test, we dusted off the same setups that we used in our Ryzen 9 3900X review but updated them with the latest BIOSes, drivers and OS updates that were available as of October 20. Both systems used Nvidia GeForce RTX 2080 Ti cards. For the Intel side, we first retested the Core i9-9900K, then swapped it for the Core i9-9900KS and re-ran the tests. Both setups also used Corsair H80i V2s with their fans and pumps set to 100 percent.
We rose above all of the nuances and politics of running Intel’s Multi-Core Enhance and AMD’s Precision Boost Overdrive. We just left them as they were set on the motherboards, with the latest BIOSes.
3D Modelling and Rendering performance
First up is Maxon’s Cinebench R20. This test uses the 3D rendering engine Maxon sells in its commercial Cinema4D modelling application (and also licenses to third parties such as Adobe to use in Premiere CC). It’s long been a poster child of multi-core and multi-threaded efficiency. Generally, CPUs that have more cores and threads do better.
No surprise, then: While the Core i9-9900KS is a little faster than the Core i9-9900K, 8 cores just can’t beat 12 cores. The Ryzen 9 3900X walks away with test.

Because most mainstream and popular applications (including Photoshop) run on only one thread, we also ran Cinebench using a single CPU core. Intel typically has the lead here, but it’s actually a mixed bag, with the Core i9-9900KS slightly faster than the Ryzen 9 3900X. The Core i9-9900K is actually third, which surprised us, but the reality is this is mostly a tie.

We also like to gauge mult-core performance using the Corona Render engine. It’s a third-party, unbiased photorealistic renderer, which means it doesn’t take any shortcuts when rendering a 3D model. Like any 3D rendering engine, it’s also very efficient with core and thread count. For comparison, we left in the result from a Ryzen 7 2700X CPU, though that result was not obtained with the latest BIOS, OS or drivers. The winner, no surprise, is the 12-core Ryzen 9 3900X.
Again, if you were expecting more out of an “all-5GHz CPU,” you shouldn’t. In our experience clock speed often doesn’t trump core count in multi-threaded tasks. We see nothing here to change that view.

We’ll cut our 3D modelling tests a little short, because the results are likely all the same, with the 12-core battering both 8-core chips. We’ll end on V-Ray Next, which is an updated version of the Chaos Group’s V-Ray Next renderer. V-Ray Next is a physically based renderer and, well, like the others here, more cores equal more performance. Again, we left the score derived from the Ryzen 7 2700X for reference, though it was run with an older BIOS. But yes, the last 3D rendering test again proves that 8<12.

Video encoding performance
Like 3D rendering and modelling tasks, video encoding usually leans heavily on CPU cores and threads. However, we also find most video encoders don’t scale as efficiently as 3D rendering engines do. Other factors play a role, such as memory bandwidth, dedicated hardware for encoding, and support for special instructions of a CPU.
Our first test is Cinegy’s Cinescore benchmark. The test is designed to measure performance of commercial off-the-shelf hardware (that’s the PC, folks) for media and broadcast work. Tasks focus on SD, HD, UHD, and 8K resolutions with various codecs (including Cinegy’s own Daniel codec). The test works by loading samples into system RAM, where the performance is measured mostly independent of storage limitations.
The winner is AMD’s Ryzen 9 3900X, but it’s not the crushing victory the CPU saw in 3D modelling. In fact, the Ryzen 9 3900X is only about 12 percent faster in Cinescore than the Core i9-9900KS, even though the Ryzen has 50 percent more cores. As we said earlier, video encoding typically doesn’t scale with core and thread count, and it also hits diminishing returns far quicker than 3D rendering and modelling.

Cinescore is aimed a bit higher than most consumer video needs, so we also run a test more people can relate to: Adobe’s Premiere Creative Cloud. It’s probably the most popular non-linear editor and is used by the majority of small- to medium-sized businesses for video editing. (Eat your heart out, Final Cut Pro.)
For our test, we take a real-world video project shot on a Sony Alpha camera at 4K resolution. We take the three-minute video and output it using the Blu-ray preset, with the maximum render option checked. We also set Premiere CC to do the encode using the CPU rather than the GPU. This may sound odd, but there are indeed video snobs who consider CPU-based encoding as the gold standard.
We’ve found that Premiere CC typically scales with core count up into the low teens. The Ryzen 9 3900X again finds itself in front—but not by much. While 16 percent faster is great, it also doesn’t quite map out with the fact that it has 50 percent more cores to throw at the work.

Before we finish off Premiere CC, we realize that a lot of people prefer the stupidly good speed of GPU encoding. So we take the exact same project we used above and encode it using the GPU.
You’d think that with the GPU supposedly doing all of the heavy lifting the CPU would no longer matter, but we’ve found it does—and apparently clock speed matters, too. As you can see, when doing a GPU encode both Intel CPUs suddenly take a commanding lead in Premiere CC.

Generally, the Ryzen 9 3900X leads in multi-threaded heavy workloads, and the Core i9-9900KS leads in single-threaded workloads. That’s about all you need to know. We’ll again summarize the situation with Cinebench R15 down below but that’s pretty much the story so far.
Keep reading for the lowdown on gaming performance.
Core i9-9900KS Special Edition Gaming Performance
It was clear for months that the Core i9-9900KS SE wasn’t going to win a multi-core battle with Ryzen 3000 chips. As we explained when we compared the Core i9 to Ryzen 9, Core i9’s expected strength was always going to be in gaming.
There’s a balance in gaming among CPU and GPU performance, display resolution and frame rate, and the game itself. The higher the resolution and the more graphically intense the game, the more the GPU matters. The lower the resolution, and the less graphically intense the game, the more the CPU will matter.
We established with our Ryzen 9 3900X review that at higher resolutions, the contest between the Ryzen 9 3900X and Core i9-9900K shrinks almost to nothing. Does being able to Turbo Boost up to 5GHz on all cores change that equation?

Our first test is Shadow of the Tomb Raider, which we run at the highest-quality setting preset at 2560×1440 resolution. It’s a two-way tie for first between the Core i9-9900K and the Core i9-9900KS Special Edition. As we said earlier, running a graphically intensive game such as Shadows of the Tomb Raider at a resolution of 2560×1440 makes this an all-GPU load. The Ryzen 9 3900X follows pretty closely.

What happens if we run it at the most common resolution today: Full HD or 1920×1080, which now makes the GPU less of a bottleneck? We see the gap widen between the Intel and AMD to about 11 percent, up from the 5 percent we saw at the higher resolution. For the most part, you can expect gaming performance between both the Core i9 chips at higher resolutions to be so close it won’t matter to most. That’s the conclusion we drew before, so the rest of our runs will be at 1920×1080.

Our next game is Deus Ex: Mankind United. This game was one of the first to optimize for AMD when Ryzen was introduced, so it should offer more of a neutral view. Even at 1920×1080 resolution, both of the Core i9 CPUs are essentially tied. Both also have about a 7-percent lead over the Ryzen 9 3900X. If you were expecting that extra few hundred megahertz of the Core i9-9900KS to kick in, so were we.

Fortunately for the Core i9-9900KS chip, it finally takes a more definitive lead in Far Cry 5’s benchmark. Unfortunately, it’s a small difference at roughly 5 percent over the Core i9-9900K. The showdown between the Ryzen 9 3900X and the Core i9-9900KS SE is what you care about, and just like old times, the Core i9-9900KS SE opens up a 26-percent increase over the Ryzen 9. We attribute this mostly to the clock speed advantage the Intel chips have, though game optimizations likely also helped. What is clear is the Core i9 is the winner. Period.

Coalition’s Gears of War 5 is brand-new and also, apparently, a decent GPU hog. We ran the game on its Ultra preset with the high-res texture pack installed. The new Core i9-9900KS SE opens up about a 7-percent performance gap over the Ryzen 9 and small 3-percent gap over its older sibling. Basically, no big whoop between the chips even at 1920×1080.

Ashes of the Singularity was one of the poster children for multi-core gaming performance under DirectX12. Our experience in the past indicates it hits a diminishing return on CPU cores fairly early. It’s still worth running, but the results above (using the Crazy preset and CPU-focused setting) says you can’t make the wrong choice.

Not all games push graphics to the wall. In fact, the most popular ones can be built on older engines and are designed to run on lower-cost hardware to reach as wide an audience as possible. One such game is Ubi’s Rainbow Six Siege, which we run on its Ultra setting. The Core i9-9900KS SE leads the way with about a 14-percent gap over the Ryzen 9 3900X. And yup, if you’re looking at upgrading from your Core i9-9900K, don’t, as you’ll get a mere 3-percent bump.

The last game we’ll show is Counter-Strike: Global Operations. A tremendously popular eSports game, CS:GO performance for normal users doesn’t matter. For actual competitors who have the hand-eye coordination of an Wild West gunslinger, anything less than several hundred fps is failure. We run the game at 19×10 resolution set to high quality and use the FPS benchmark from the workshop to measure frame rates.
The winner by 21 percent over the Ryzen 9 3900X is the Core i9-9900KS SE, with no less than 480 fps overall. Mind you: When the game wasn’t dragging frame rates to 150 fps for the intense smoke particle sections, we were seeing 700 fps. So yeah, if the Ryen 9 3800X’s 394 fps isn’t enough, you have your answer.
Keep reading for thread-by-thread performance and objective bang-for-buck analysis.
Threadscaling performance
We’ll close our testing by looking at performance isolated by CPU core count. For that we use Cinebench R15 and run it using from 1 thread to the maximum number of threads each CPU has. While Cinebench is a 3D modelling application and isn’t the same as, say, running Excel or Chrome, it does give us an approximation of how the CPU responds under a spectrum of loads.
First up, the Core i9 9900KS Special Edition vs. the Core i9-9900K. For the most part, the Core i9-9900KS has been dogged at every turn by its sibling separated at birth, the Core i9-9900K. If you doubt the Core i9-9900KS SE is faster, though, you can see below the impact of each chip’s top boost speeds.

Another way to look at the difference is by percentage. You can see on a single-threaded load where both CPUs are rated to hit 5GHz, it’s basically a tie. From there though, the 5GHz boost scores give the Core i9-9900KS a very real, but not huge advantage over the Core i9-9900K. Is it worth $25? Probably. Would we pay $25 for only a 4- to 7-percent difference? Maybe. Remember, you can also brag to your friends that you have an “all-core 5GHz CPU,” and that’s really priceless.

The tougher road for the Core i9-9900KS Special Edition is against the Rzyen 9 3900X. The Core i9-9900KS Special Edition’s 5GHz boost clocks give it clear advantage on the left side of the graphic, but the sheer number of cores in the Ryzen 9 3900X gives it a commanding lead on the middle to the right in the graphic below.

If you want to see how deep the hole is for the Core i9-9900KS Special Edition, just look at the percent difference below. You can see the Ryzen 9 3900X just running away from the 8-core Core i9 chip—5GHz or not. Basically by 8 threads, the Core i9-9900KS Special Edition is under water and continues to just get deeper.

Price analysis
This next graphic is our last, and is the simple metric of how much you’re paying for each CPU thread. This is somewhat limited as it doesn’t speak to the “quality” of that thread or its performance, but as a raw, 5,000- foot view of cores per buck we find it handy. And frankly, most consumers don’t look at the performance of the cores. They look at the sheer number the way they, well, look at megahertz.
The chart shows that while we appreciate Intel’s moderated price on the Core i9-9900KS SE, it doesn’t compare to the deals you can get for AMD’s Ryzen chips. Even if you subtract the “bulk” price of the high-core-count CPUs (they may be cheaper, but you have to buy a ton of them) Intel’s current pricing on the Core i9-9900KS SE can’t compete.

When the best isn’t good enough
In 2013, AMD released its FX-9590 Black Edition CPU, which heralded up to 5GHz turbo clocks at an astounding 220-watt TDP, but delivered unimpressive performance against Intel’s best and brightest. It was, essentially, a last-ditch effort to get attention for a chip that had been passed by.
Now more than six years later, there is an Alanis Morissette sense of irony with Intel’s all-Turbo Boost Core i9-9900KS, which simply cannot outrun its AMD counterpart in many tasks.
To be fair, the situation for the Core i9-9900KS isn’t as dire as it was for the FX-9590 Black Edition. That 8-core FX-9590, after all, lost most matches to Intel CPUs with only four cores. You would have had to look far and wide to find something, anything, the FX-9590 was better at.
World’s Best Gaming Processor: True
The Core i9-9900KS can, at least, hold its head high as the “world’s best gaming processor.” We have no doubt of that, and the numbers you’ve seen here prove that.
The problem is, it’s not like nerds were asking for Intel to raise the bar on gaming—where it already leads with the previous Core i9-9900K chip. In fact, that was proclaimed as the “best gaming CPU” when launched last October, and if not for the Core i9-9900KS, would still be top dog.
No, what Intel fans wanted were more cores to help push back against Ryzen—or if not, then hyper-competitive pricing.
With the Core i9-9900KS SE, we get essentially the world’s new best gaming CPU, but nothing that really changes the CPU landscape for desktop users. That small disappointment will ultimately vex the Core i9-9900KS Special Edition.
Should you buy the Core i9-9900KS?
This hardly means the Core i9-9900KS Special Edition is bad. CPUs are not one-size-fits-all. There are indeed many people who might want to buy this CPU, so we’ll help you decide.
The Core i9-9900K customer: The most obvious buyer is the consumer who’s already decided to buy a Core i9-9900K chip. If you’re already paying $490 for a Core i9-9900K chip, an extra $25 or so is worth it for essentially a binned-out, A-grade CPU.
You run Intel-loving apps: Intel has a large army of employees working on software development. That means there are a lot of apps and games optimized for Intel. You can hate it or criticize it, but if at the end of the day, it gets you more performance, the Core i9-9900KS is the right choice for you work.
The Intel upgrader: If you’re already in the Intel ecosystem and need more performance (and you thought ahead and bought a higher-quality motherboard), it just doesn’t make sense to dump it all, switch to Ryzen and take a bath on the motherboard and deal with a complete rebuild of the OS. Just pluck out that 6-core, 6-thread Core i5, drop in the 8-core, 16-thread Core i9-9900KS, and you’re back in business. The path of least resistance is well-trod for a reason.
The pro gamer: If you absolutely, positively have to have maximum fps to decrease latency and response time, then look no further than the Core i9-9900KS. It’s almost as though Intel sat down and made a CPU just for you.
The 100-percent gamer: We don’t know if this 100-percent-gamer person really exists, because we know people use their PCs for other tasks. But if you only play games and you can’t decide between a Ryzen 9 3900X and Core i9-9900KS Special Edition (both roughly $500), we can straight up say the Core i9-9900KS Special Edition will perform better probably 99 percent of the time. And yes, we’ll also point out that, maybe a Ryzen 7 or even Ryzen 5 as well as Core i7 or even Core i5 is a better use of your funds. But if you’re dead-set on a top-tier gaming chip, look no further.
Everyone else: Everyone else not on this list, frankly, is better served by the 12-core Ryzen 9 3900X, because of its additional multi-threaded performance and still fairly decent gaming performance.