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AMD Ryzen 9 3900X vs. Intel Core i9-9900K

The years 2019 was a great year for AMD, with new CPU and graphics card launches that captured massive attention from the industry and hardware fans alike. But that’s not to say it doesn’t have stiff competition in both camps. Its new Ryzen 3000 CPUs go head to head with Intel’s best on price, but how do they compare on performance?

With new hardware in hand, there are great comparisons for us to make throughout the new range of Ryzen chips. At the top end, for around $500, we have the Core i9-9900K versus the Ryzen 9 3900X. Which will be the best chip of them all?

By the numbers

AMD Ryzen 9 3900x
Dan Baker/Digital Trends

Only eclipsed by its 16-core successor, the Ryzen 9 3900X is an extremely powerful mainstream CPU packing fantastic specifications. The Core i9-9900K is no slouch, however, and by the numbers, they’re pretty comparable.

Intel Core i9 9900K AMD Ryzen 9 3900X
Process node 14nm 7nm
Cores 8 12
Threads 16 24
L2/L3 cache 2MB/16MB 6MB/64MB
Base clock speed 3.6GHz 3.8GHz
Boost clock speed 4.7GHz (all cores)
5GHz (one core)
4.1GHz+ (all cores)
4.6GHz (one core)
Graphics Intel UHD Graphics 630 No
TDP 95w 105w

The 3900X has more cores and threads, while Intel’s chip has the stronger clock speed, especially when it comes to single-threaded workloads. Most games now use a handful of cores, so unless you’re overclocking, you won’t typically see 5GHz frequencies when gaming on a 9900K.

The 3900X can boost to 4.6GHz on a single core, but will be closer to 4.1GHz if using all cores and threads at the same time. AMD’s automated overclocking can take it up to 4.3GHz in some cases, though it’s very much dependent on your motherboard, BIOS revision, and cooling.

The 3900X has seen a major increase in instructions per clock over its second-generation predecessors, so it’s more powerful than the 9900K clock for clock. Its huge L2 and L3 cache effectively eliminate the memory latency concerns from the 2nd-generation chips, too.


Intel Core i9- 9900K
Intel Core i9- 9900K

Intel has held a performance edge in gaming for more than a decade, and even with AMD’s fantastic first- and second-generation Ryzen CPUs, that held true. But no longer.

In our gaming tests with Fortnite, Civilization VI, and Assassin’s Creed Odyssey, the 3900X beat out the 9900K — a CPU previously hailed as the best gaming chip ever made — on almost all settings, showing a slight lead. That might not be the crushing numbers that AMD fans hoped for, but this is the first time that a high-end AMD CPU beat the Intel competition in gaming in more than 10 years.

The 3900X showed a decent lead in 3DMark, while in Assassin’s Creed Odyssey, it matched the 9900K on high settings and exceed it on low settings. In Fortnite, the 9900K shot ahead of the 3900X with high settings, but with over 250 FPS in all of our tests, that difference hardly matters.

We saw the most drastic difference in Civilization VI.  Across high and low settings, the 3900X beat the 9900K. Most grand strategy games stress the CPU more than the GPU, as the processor handles A.I.-driven opponents and multiple interconnected systems. As with Fortnite, both processors delivered above 150 FPS across our trials. AMD’s edge in both tests — not in a single test, as was the case with Fortnite — shows its capability as a gaming CPU.

Price is an important factor, though. Although the 9900K was more expensive than the 3900X at launch, it’s slightly cheaper now (a new position for Intel). You can commonly find a 9900K for around $400. The 3900X is more expensive, but not by much, typically selling for around $430.

It is important to consider the ongoing problems Intel faces with CPU performance hindered by Spectre mitigation, too. Those may continue as new bugs are found in the future, where AMD’s chips are typically more robust against these kinds of exploits.


Heavily multithreaded productivity tasks like video transcoding and editing have been more AMD’s wheelhouse for the past couple of years, with its Ryzen and Threadripper chips competing directly and even pulling ahead of Intel’s more expensive options. With the 3000 series, and specifically the 12-core, 24-thread 3900X, AMD has beaten not only Intel’s mainstream chips (the 9900K included) but will even put some of its older Threadripper cousins out to pasture.

At E3 2019, AMD provided statistics of its 3900X pitted against one that’s more than twice the price: The 12-core, 24-thread, $1,200 Intel Core i9-9920X. And it still cleaned up.

When we received the 3900X for testing, we pitted it against its true rival: The 9900K. Unsurprisingly, the new AMD CPU proved dominant once again.

In Geekbench and Cinebench, the 3900X decimated the 9900K in multithreaded performance, though its reduced clock speed meant it fell just shy of the Intel competition in single-threaded tasks. In the real world Handbrake 4K transcoding test, the 3900X proved almost 25% faster than the 9900K — a sizable advantage delivered by the extra cores/threads of the AMD chip.


Efficiency isn’t as important on desktop chips as it is with laptops, as there’s no battery life to consider. But heat is an important factor, and the more power a CPU requires, the more heat it outputs. That’s where the somewhat marketing-driven TDP figure comes from.

By the numbers, Intel’s 9900K is the more efficient chip, with a rated TDP of 95 watts, while the 3900X has a TDP of 105 watts. But that’s not the full story. Intel’s TDP ratings tend to relate to its base clock, rather than its sustained boost. AMD’s are much closer to the power it pulls when at its highest clock speeds.

Research into power demands from Intel’s 9900K around its launch showed it drawing far more power than its TDP rating. Tom’s Hardware reported that while it remained under its TDP during gaming, when doing heavily multithreaded workloads over prolonged periods, it could require more than 200 watts. That number could increase to 250 watts if overlocked.

We didn’t test the 3900X’s power draw, but other reviewers have, and Anandtech found it never pulled more than 142 watts when fully loaded. That makes it a more efficient chip than the 9900K too. And that’s AMD’s big selling point with its Zen architecture: More performance per watt.

The 3900X is the new CPU king

AMD Ryzen 9 3900x
Dan Baker/Digital Trends

We were excited for the 3900X before it launched based on prerelease numbers and speculation. Now we can report that after tests, we’re even happier.

The 3900x performance outshines the 9900K, and it exceeded most of our gaming and limited task test categories, despite Intel having been the long-held champion of gaming. The 3900x far exceeded when it came to multithreaded workloads. On top of that, you can also use a smaller cooler for your setup because the 3900x’s TDP is low.

AMD has achieved an impressive accomplishment here; we haven’t seen these performance levels since the Athlon 64. The 3900x also sports the best mainstream CPU in AMD’s entire catalog of products. They have successfully usurped Intel’s throne. Intel cut down prices in response and established a new generation of even faster CPUs to combat AMD’s best.

Even with the reduced costs, Intel’s eight-core 9900K just doesn’t make the grade. The 3900x has better performance quality, cores, and threads— even though it costs $50. Although it’s not a dealbreaker, AMD’s chip does not include integrated graphics. The price for this chip is still budget-friendly, and it’s frankly the only negative we found for the 3900x.

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