Watch out, Threadripper; take cover, Core i9! AMD's new top-end mainstream CPU for gamers and content-creating power users is the $499 Ryzen 9 3900X, and it's brute force in silicon form.
This third-generation, 12-core Ryzen processor, based on the same AM4 platform and socket as earlier Ryzens, refines the standout features the Ryzen brand is known for, including power efficiency, simple overclocking, and very competitive performance per dollar.
Despite its new name and guts—this is the first CPU to bear the "Ryzen 9" moniker, and one of the initial wave of Ryzen 3000 CPUs to support the Zen 2 microprocessor architecture—it's an evolution of AMD's consumer CPUs, with core features similar to its first- and second-generation Ryzens.
That means it's an excellent choice for PC-building enthusiasts and upgraders.
It's not markedly better in every use case than Intel's comparable Core i9-9900K, but if you need all the cores and threads you can get, it's a superb, Editors' Choice value among power CPUs, even elbowing in on the lower-end chips in AMD's own beastly Ryzen Threadripper line.
A Massive Core and Thread Count
The Ryzen 9 3900X's standout feature is its massive core count.
Twelve-core CPUs like this one are rare in the consumer PC world; before this, you had to step up to AMD's Ryzen Threadripper line or Intel's Core X-Series to see core counts like these.
Even most high-end pre-built gaming desktops come with "just" six- or eight-core chips.
To truly take advantage of the Ryzen 9 3900X's power, you need to be running the latest applications that are designed to run on as many CPU cores as possible.
(Those tend to be content-creation apps such as video or photo editors; games tend to hew to the lowest common denominator.)
Since the Ryzen 9 3900X also supports multi-threading, two computing tasks can run simultaneously on each processor core, for a maximum of 24 threads of compute power.
That matches the spec of the 12-core, 24-thread (12C/24T) AMD Ryzen Threadripper 2920X, the lowest-end of the elite AMD Threadripper lineup aimed at content creators and other creative professionals.
It's also significantly more cores and threads than the previous mainstream Ryzen flagship, the 8C/16T AMD Ryzen 7 2700X.
That chip, in turn, offers more threads and cores than its direct competitor, the 6C/12T Intel Core i7-8700K.
Here is how it stacks up versus the rest of the new Ryzen 3000 line, five of which are rolling out at the same time...
Like the Ryzen 7 2700X does, the Ryzen 9 3900X also offers a core- and thread-count advantage over its own direct Intel competitor, the Intel Core i9-9900K ($370.44 at Amazon) .
Both chips have the same $499 MSRP, but the Intel has eight cores and 16 threads.
A higher maximum clock speed remedies that deficiency somewhat, however.
The Core i9-9900K has a base speed of 3.6GHz and a maximum boost clock of 5GHz, versus the Ryzen 9 3900X's 3.8GHz base and 4.6GHz boost.
(Of course, you can overclock either chip; Intel's "K" series CPUs come unlocked, while all of the Ryzens are unlocked.)
Put all of these basic specs together, and it's clear that the consumer CPU market remains just as competitive as it was when AMD announced the first Ryzen chips in early 2017.
Deciding between Intel and AMD, therefore, comes down somewhat to subtle performance differences and ancillary features, but at the heart of it all: how much you need lots of cores and threads at your command.
And the Ryzen 9 3900X has plenty of advantages here.
An Evolved Processor Architecture
The Ryzen 9 3900X is the first of two chips we've tested that uses AMD's Zen 2 microarchitecture (the other being the AMD Ryzen 7 3700X).
Zen 2 is what makes 12 cores possible—the initial Zen architecture only supported a maximum of eight cores.
Chips on the Zen 2 microarchitecture also feature the debut of a smaller 7 nanometer (7nm) process node.
Zen silicon was built on a 12nm node, and most Intel consumer chips currently on the market are made on 14nm or 12nm nodes.
Reducing the node size is key to improving a chip's energy efficiency.
It doesn't necessarily improve clock speeds, though.
The Ryzen 9 3900X's base clock is actually 100MHz lower than the Ryzen 7 2700X's, for example.
(The 2700X was the highest-end AM4 chip before the current generation rolled out.)
Besides better efficiency and more cores, Zen 2 also features other behind-the-scenes improvements that boost the Ryzen 9 3900X's appeal.
Some of these involve hardware changes, including double the bandwidth of the bus that enables different parts of the CPU to communicate with each other, a feature that AMD refers to as "Infinity Fabric."
Others are software improvements to how the Windows operating system runs on Ryzen, including the ability to switch between clock states more quickly.
Clock-state changes in Zen-based CPUs take approximately 30ms, while they take only 2ms in Zen 2, according to AMD.
In a simple sense, the improvement is akin to changing gears more quickly in a transmission.
To take advantage of this, you'll need to have the Windows 10 May update installed, version 1903.
(For more on the fine points of the Zen 2 architecture, check out this deep dive on our sister site ExtremeTech.)
A New Express Lane
In addition to a new microarchitecture, two other standout additions roll out with the latest Ryzen lineup: support for the fourth-generation PCI Express standard for connecting peripherals and add-in cards, and improvements to memory speed and latency that help boost the performance of certain graphics-intensive games.
AMD achieves support for the new PCI Express (PCIe) Gen 4 through a brand-new AMD X570 chipset; it's the first mainstream PC-compatible platform to support PCIe 4.0.
(See our guide to all of the X570 motherboards we saw at Computex 2019.) The main benefits of PCIe Gen 4 are added bandwidth for video cards and storage components like SSDs.
Storage will be the more likely early beneficiary.
PCI Express 4.0 M.2 SSDs will soon be available from the likes of ADATA, Corsair, Gigabyte, and others, offering throughput speeds well above the approximate 3,500MBps ceiling of PCIe Gen 3.
If you're planning on building a new system from scratch with the Ryzen 9 3900X, you'll also want to invest in a new X570-based motherboard to take advantage of these increased speeds in the future.
We tested the Ryzen 9 3900X with MSI's MEG X570 Godlike motherboard, which includes its own built-in fan over the chipset to keep things extra cool, a feature that's relatively uncommon even on high-end gaming motherboards but a common trait among X570 models.
(The chipset runs at a higher-than-ordinary wattage, necessitating active cooling.) The Ryzen 9 3900X is also compatible with many (but not all) existing AM4-based motherboards, though, which means that if you're looking to upgrade just the CPU in your existing Ryzen-based PC, you may not need to buy any other components.
(Check out this piece, again from ExtremeTech, for the complexities of which older AMD AM4 chipsets and boards will be compatible with the Ryzen 3000 series CPUs; where an older board will work, a BIOS upgrade will almost certainly be involved.) Pre-X570 motherboards will not bring the PCIe 4.0 support with them, however.
Third-generation Ryzen chips also have support for faster memory and caches that are twice as large as the ones in previous generations.
With memory running at a peak of 3,600MHz (assuming you have compatible RAM) and the whopping 70MB of L3 cache in the Ryzen 9 3900X (here dubbed "GameCache"), the system can address available memory much faster.
This is especially important for gamers, since the performance of some games can be dependent on a CPU's ability to access memory, especially at screen resolutions below 4K.
(At the highest resolutions and detail settings, the graphics card tends to be limiter.) It's also an area in which earlier Ryzen chips have been a bit deficient, under certain resolution/card combinations, versus their Intel counterparts.
PC Labs did some deeper-than-ordinary testing in that regard; more on that in a bit.
Other Ryzen Benefits
As with some previous high-end Ryzen chips, AMD offers a premium Wraith cooling fan in the box with the Ryzen 9 3900X.
The cooler, the Wraith Prism, features a nifty ring of RGB lighting with support for the Chroma lighting system from Razer, which means you can sync the LED effects with your other Razer Chroma peripherals, such as keyboards and mice.
Even without Chroma, you get a cool rainbow effect.
(If you mean to do any kind of serious overclocking with the Ryzen 9, a liquid cooler is recommended, however.)
All Ryzen chips use the Ryzen Master Windows app for quick settings adjustments without having to shut down your PC and enter the BIOS.
Among other capabilities, Ryzen Master lets you see the current state of each CPU core, and highlights which of the cores are the best performers.
This is a boon to overclockers who want to boost the clock speed of individual cores, something you can also do with precision within Ryzen Master.
Intel offers similar capabilities with its own apps, including the Extreme Tuning Utility, but I slightly prefer the visual layout of Ryzen Master.
AMD updated the app to version 2.0 concurrent with the Ryzen 3000-series third-generation CPU release.
Differences include a redesigned dashboard interface and the ability to switch among Default, Precision Boost Overdrive (automatic overclocking), and Manual modes without restarting your PC.
In addition to the Ryzen 9 3900X, as mentioned, four more third-generation Ryzen chips go on sale at the same time: the eight-core Ryzen 7 3800X and Ryzen 7 3700X (the latter which PC Labs also tested, as mentioned), and the six-core Ryzen 5 3600X and Ryzen 5 3600.
To reiterate those prices...
All are unlocked for overclocking, but adjusting the clock speeds either manually or with AMD's presets (described below) will void the standard three-year warranty.
Also in the hopper is a 16-core Ryzen 9 3950X CPU, announced just before E3 2019, but that chip is not due until September.
Let's Get Testing...
In addition to the MSI X570 motherboard, our test setup for benchmarking the Ryzen 9 3900X includes 16GB of G.Skill DDR4-3600 memory, a Corsair MP600 PCI Express Gen 4 SSD boot drive, and an Nvidia GeForce GTX 1080 Founders Edition card to handle video output during the CPU tests.
(Like earlier Ryzen chips not ending in "G," these new Zen 2-based Ryzens do not have on-chip graphics, so a video card is necessary.) For all tests, we ran the memory at its maximum 3,600MHz speed, using the Godlike board's top supported XMP profile.
We used AMD's in-box Wraith Prism cooler for these tests, which is plenty powerful enough to handle the heat generated from the Ryzen 9 3900X at stock settings.
At 105 watts, the chip's thermal design power (TDP) is slightly higher than the 95-watt TDP of the Intel Core i9-9900K, but it's still remarkably low for a 12-core CPU.
The lowest-end Ryzen Threadripper, the 2920X, by contrast, has a massive 180-watt TDP for the same number of cores, and a much bigger die.
We test CPUs using a variety of synthetic benchmarks that serve up proprietary scores, as well as real-world tests using consumer apps like Apple's iTunes and 3D games like Far Cry 5.
Overall, the Ryzen 9 3900X offers remarkable performance for a 105-watt CPU, especially on tests that take full advantage of its 12 processing cores and 24 threads.
Multicore over single-core scenarios are the Ryzen 9's big strength.
Cinebench R15
Maxon's 64-bit Cinebench R15 synthetic benchmark offers a good overview of performance on many different types of demanding apps.
It's a CPU-centric test that gauges both the single-core performance and the multicore performance of a processor.
The resulting scores are proprietary numbers that represent the CPU's capabilities while rendering a complex 3D image.
With a score of just under 3,000 on the Cinebench all-cores test, the Ryzen 9 3900X far outpaces the Core i9-9900K and gives even the Ryzen Threadripper 2950X a run for its money.
That's especially impressive since the 2950X is a more expensive chip, on the more expensive AMD X399 platform, with 16 cores.
Also consider the performance delta between the Ryzen 9 3900X and the around-$2,000 Intel Core i9-9980XE Extreme Edition, if you're tempted by that 18C/36T Core X-Series chip at four times the price.
The single-core performance on the Cinebench test is quite competitive, albeit less impressive.
POV-Ray 3.7
The POV-Ray benchmark is a synthetic, highly threaded rendering test that offers a second opinion on the Cinebench results.
Here, the Ryzen 9 3900X was quite competitive on the multicore test, recording a 16-second advantage over the Core i9-9900K, albeit a bit behind on the single-core.
Although many modern complex apps are designed to run on multiple cores and threads, single-core performance is nevertheless still important if you rely on legacy software.
Many older games, especially those built on DirectX 9, use just one or two cores.
And manufacturing variabilities mean that there are slight variations in each core's maximum performance, so better performance from each core "lifts all sails," as an AMD spokesperson puts it.
iTunes 10.6
For a real-world look at single-core performance, we use an older version of Apple's iTunes to encode a series of music tracks.
This is legacy software, in spades—Apple has already announced iTunes' extinction—and it's decidedly single-threaded, which means that piling on more cores and threads doesn't help here...
Indeed, we see that all of the Intel chips in the chart above surpassed all of the Ryzen chips on this test.
Both third-gen Ryzens did better than their predecessors (better even than the Threadripper 2950X) but the fact remains that in general, parallel Intel chips offer better single-core performance when running certain apps.
Handbrake & Blender
Many gamers who can justify spending $500 on a CPU need it for more than just frag fests.
If you're planning to run seriously demanding apps that lap up the Ryzen 9 3900X's cores and threads, you'll want to pay attention to the results of our Handbrake and Blender encoding tests and workstation-class benchmarks like POV-Ray above.
The Ryzen 9 3900X took just 4 minutes and 20 seconds to encode a 12-minute 4K video to 1080p, besting all comers except for the Threadripper 2950X (and that, not by much) and...
