AMD Ryzen 9 5900X vs. Intel Core i9-10900K: Which High-End CPU Is Right For You?

As 2020 draws to a close, we're taking a look at two of the biggest desktop CPU launches of the year to see how they stack up side by side. Intel's top-end mainstream-platform CPU for desktops, the Core i9-10900K, may not have all the leading-edge feature glory and new architecture of the new(er) AMD Ryzen 9 5900X. But does that technical debt translate into less performance in the places where it counts the most?

Just in case the Editors' Choice award above for the Ryzen 9 5900X didn't already tip you off, the brass ring this time will go with the Red Team rather than the Blue Team. That said, let's dig into the features, price, and performance of these two flagship options to see which company is producing the best high-powered processors in the market today.

Ryzen 9 5900X vs. Core i9-10900K: Specs and Architecture

To start off our comparison between these two top-end chips, let's take a peek at some base specs...

As you can see above, there's already a bit of a problem trying to put these two head-to-head: the nearly-$500 10-core Intel Core i9-10900K seems to be missing two cores...or the $549 12-core AMD Ryzen 9 5900X brought two extra cores to the party, depending on how you want to look at it.

But on pricing, while $488 might sound reasonable enough given the Core i9-10900K's two-core deficit, the street price of the Core i9-10900K is, just about everywhere you can find it, anywhere between $549 and $599. (And that's if it's even in stock in the first place.)

This puts it right in the crosshairs of the $549 AMD Ryzen 9 5900X on price, but that's where the similarities end.

The 10-core Intel Core i9-10900K, like five years of desktop processor releases before it, is based on a 14nm lithography process, now aged up to what's been dubbed here in 2020 a "14nm++" process. The company continues to use a monolithic die approach to its architecture, and although the 14nm process is more than five years old at this point, Intel's engineers have proven it to be a solid foundation for constant iteration and subtle improvement over time.

Meanwhile, like the preceding generation of Ryzen chips, the new Zen 3-based Ryzens are based on the company's 7nm lithography. They continue to use a multi-die "chiplet" approach, which helps to increase the yields of its production process. This gives AMD the ability to throw more cores into the chip package at a competitive price, keeping the cost-per-core ratio between the 5900X and 10900K a Ryzen advantage out of Intel's reach.

The Ryzen 9 5900X features 64MB of available L3 cache to the Core i9-10900K's 20MB, and a TDP of 105 watts to the Core i9-10900K's 125-watt requirement. Which brings us to a quick sidebar about the platform.

WINNER: AMD Ryzen 9 5900X, in per-core value

Ryzen 9 5900X vs. Core i9-10900K: Platforms and Compatibility

The short version of these two foundational topics?

• AMD: One socket, Socket AM4, that works (with some recent caveats) with three generations of CPUs (and counting).

• Intel: Never more than two generations of Core chips per socket before a new socket and motherboards show up.

AMD continues to do everything it can to grandfather as many motherboards as possible into the Ryzen 5000 Series ecosystem, while Intel has stuck to its usual pattern: a move from 9th Generation Core's LGA1151 to a new, incompatible LGA1200 socket for the 10th Generation "Comet Lake-H" CPUs, of which the Core i9-10900K is the family head.

Also, the top-end chipset for 10th Generation Core processors, Z490, comes on boards that don't even have support for PCI Express 4.0 (yet). Granted, they could be forgiven, since PCIe 4.0 doesn't make much difference (yet!) in overall system performance numbers, outside of peak storage-benchmark speeds with cutting-edge SSDs, but there's the future-proofing aspect to think of.

By contrast, the AMD Ryzen 9 5900X works on any AM4-based motherboard between the X570 and B350 platforms. We recommend checking with your manufacturer for proper BIOS support before picking up a Ryzen 9 5900X sight unseen, though. But you might be able to drop one into an older, existing motherboard, whereas with a 10th Generation Intel CPU like the Core i9-10900K, you'll need a board with the new LGA1200 socket.

Finally, PCI Express 4.0 is standard issue for all motherboards based on B450, B550, or X570 chipsets. Point and round, to AMD.

It's not all sour grapes for Intel, though. The company maintains its lead on single-core boost clock speeds, at just over half a gigahertz faster between the two processors. As you're about to see, though, that spec lead doesn't always translate to a guarantee of wins once we fire up the benchmarks.

WINNER: AMD Ryzen 9 5900X, in platform longevity and compatibility

Ryzen 9 5900X vs. Core i9-10900K: Productivity Performance

So, the Ryzen 9 5900X walks into our performance benchmark arena with a two-core advantage and a roughly equal footing in street price. How does it shake out in content creation and productivity benchmarks? Let's take a look...

As we discussed at greater length in our deep-dive review of the AMD Ryzen 9 5900X, AMD's chip outright beat Intel at all of our standard benchmark tasks. Heavily multithreaded runs that scale well with more cores applied, like 7-Zip, continue to be blowouts for AMD, with the Ryzen 9 achieving a result that was 85% faster in that compression/decompression test. That's a record showing for this class of chip, and a win that's no doubt aided by the Ryzen 9 5900X's core advantage over the Core i9-10900K.

Gains in Cinebench were less drastic, by comparison, but still significant. The Ryzen 9 5900X was roughly 40% faster than the Core i9-10900K in the multi-core run, if just 5% faster in single-core. This is still impressive, though, considering that the 5900X has to make room for two more cores than the Core i9-10900K and still manages to outpace it in single-core content work. (That was also borne out in the single-core run of POV-Ray and the minimally threaded legacy iTunes test.) Single-core speed has long been a traditional strength for Intel chips versus their like-priced and similarly positioned AMD competitors. This Ryzen 9 breaks that norm.

Given the price, taken together, of the chip and the mandatory adoption of LGA1200, the Intel Core i9-10900K isn't a better deal than the AMD Ryzen 9 5900X for pure productivity, like the tasks reflected here. The Ryzen 9 5900X should be at the top of the list for content creators who need to squeeze every drop of performance out of their machines in a prosumer or a professional work environment with thread-happy software.

WINNER: AMD Ryzen 9 5900X, as a productivity- and creative-performance leader

Ryzen 9 5900X vs. Core i9-10900K: Gaming Performance

Gaming performance has also been a traditional strength of Intel's desktop CPUs, in games at resolutions where CPU performance comes into play as the limiting factor. And for a while there, Intel hung on. Through the various "Lake" generations of processor starting with "Skylake," up against its successive AMD Ryzen challengers, Intel would sustain its lead in the one area that drives lots of sales of desktop processors among PC upgraders and builders: PC gaming.

Welp, scratch another one off the list...

Though the race is closer on gaming than it is on productivity, in lightly threaded frame-rate record-setters like Counter-Strike: Global Offensive, the Ryzen 9 5900X gives our sample GPU (the still very high-end GeForce RTX 2080 Ti) the room it needs to sail to new heights at 4K by 30fps over the Intel Core i9-10900K, and at 1080p by 75fps.

That 1080p result of 679fps won't be relevant to serious gamers for at least a few more years (1,000Hz gaming monitors here we come!), but these wins were consistent across our testing in 3DMark scores and another high-refresh-capable blockbuster, Rainbow Six: Siege.

However, the Core i9-10900K and its 5.3GHz boost clock shows up to the party once more engines and thread loads are thrown into the mix. The Core i9-10900K walks away with comfortable wins in Far Cry 5 and Bioshock: Infinite, and a photo-finish win in our benchmark of Tomb Raider (2013).

Between the two, it comes down to what types of games you intend to play. However, between these two choices and a lower-end CPU on the same platforms (say, an Intel Core i5-10600K or an AMD Ryzen 3 3300X), it comes down to the resolution you plan to play at. Both the Core i9-10900K and the Ryzen 9 5900X qualify as overkill for most games played at resolutions above 1080p, so if you've got either a 1440p or 4K display, you'd be better served spending less on your CPU and shifting the rest of that budget into a beefier graphics card instead...assuming "money" is a finite thing for you.

WINNER: A draw, dependent on game and resolution

Ryzen 9 5900X vs. Core i9-10900K: Overclocking and Thermals

As two top-end chips that come close to maximizing the potential of their respective platforms, it's not a surprise that both the AMD Ryzen 9 5900X and the Intel Core i9-10900K have limited amounts of room available for overclockers to play in.

In our testing, we found that Intel has stretched 14nm to its limits. Thermal tests showed the Core i9-10900K peak at 79 degrees C (versus the Ryzen 9 5900X's 71 degrees C), but the chip takes back a win when you look at the overclocking potential.

Though both chips were overclockable to a point of stability above their stock specs—by nearly 15% in the case of the Ryzen 9 5900X—only the Core i9-10900K returned verifiably improved performance (of around 5%) on actual testing scores. The effect of our overclocking on the Ryzen 9 5900X returned either identical results, or results that fell under the line set by the original non-overclocked benchmarks.

On the software side, Intel users can download the company's Extreme Tuning Utility (XTU) tool, which features real-time control of nearly every aspect of how the Core i9-10900K behaves, while AMD's Ryzen Master utility fills a similar role for Ryzen 9 5900X owners. On this front, it's even, as each piece of software is as deeply feature-rich as the other, including internal benchmarking tools, thermal monitoring, and the option to both save and import custom profiles directly in the panel.

WINNER: A draw: AMD for thermals, but Intel for overclocking performance

The Verdict? AMD Closes Out a Banner Year

By now, it's no secret that AMD has utilized its close relationship with chip manufacturing giant TSMC to the fullest with the release of the Ryzen 5000 Series. The Ryzen 9 5900X is the company's best foot put forward against Intel's Core i9-10900K.

The Ryzen 9 5900X runs at less power, and has 20% more cores than the Core i9-10900K for close to the same real-world price. It's compatible with multiple generations of AM4 motherboards, and it universally outpaces the Core i9-10900K in content-creation tasks while trading blows with it in gaming (with ties, win, and losses alike, depending on the engine).

Intel's not out of the race yet, though, with its fourth straight desktop-CPU release on 14nm, dubbed "Rocket Lake," set to debut in the first quarter of 2021. If the company can squeeze some final gains out of its 14nm++(++?) architecture, there's a chance it could either catch up to, or perhaps edge past, Zen 3-based processors sooner rather than later.

Until then, though, for between $500 to $600, the AMD Ryzen 9 5900X is the best premium desktop processor you can get for productivity, content creation, and lightly threaded gaming at all resolutions.