AMD Ryzen 9 3900X review: Amazing multi-core CPU performance at an unbelievable price

AMD Ryzen 9 3900X
AMD Ryzen 9 3900X (Image credit: Windows Central)

AMD really turned it around with the launch of first-gen Ryzen, but it was still behind its Intel counterparts. The company continued to work on Ryzen, further reducing the manufacturing process, improving efficiency and performance, and launching an entirely new model for those seeking multithreaded performance. The new Ryzen 9 3900X promises 12 cores and 24 threads worth of AMD performance.

You'll love the AMD Ryzen 9 3900X performance

AMD Ryzen 9 3900X

AMD Ryzen 9 3900X (Image credit: AMD)

AMD released Threadripper processors to accompany desktop-class Ryzen CPUs for those who demand even more performance than what the Ryzen 7 2700X would offer. These Threadrippers (aptly named) would sport anywhere from 12 cores up to 32 — yes, that's cores and not threads. The only drawback to these processors is they don't run on AM4 motherboards, requiring a dedicated chipset and socket.

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Header Cell - Column 0 Ryzen 5 3600Ryzen 5 3600XRyzen 7 3700XRyzen 7 3800XRyzen 9 3900X
ArchitectureZen 2Zen 2Zen 2Zen 2Zen 2
Clock speed3.6GHz4.2GHz3.8GHz4.4GHz3.6GHz4.4GHz3.9GHz4.5GHz3.8GHz4.6GHz

That meant you had to not only buy the processor but swap out your AM4 motherboard if you were upgrading. That was until AMD announced the new Ryzen 9 model to fit in between the Ryzen 7 and Threadripper processors, but running on the same AM4 socket motherboards. Taking advantage of new 7nm manufacturing, AMD was able to cram in more performance in the smaller package, allowing you to enjoy 12 cores and 24 threads of performance.

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ArchitectureZen 2
Clock speeds3.8GHz4.6GHz
Cache6 MB64 MB

The Ryzen 9 3900X runs at 3.8GHz with a boost of 4.6GHz, though that number will fluctuate depending on numerous factors, including PC cooling capacity. That said, pairing the processor up with the included AMD Wraith Prism cooler and aftermarket Cooler Master EVO 212 allowed the CPU to enjoy a reliable boost speed while under load. And because the latest generation of Ryzen is more efficient, temperatures barely rose above 70 degrees Celcius (158 Fahrenheit).

AMD actually matches the core and thread count of the entry-level Threadripper 2920X with the new Ryzen 9 3900X, rocking a massive 70MB of cache. What all these numbers mean is you will be able to run more demanding tasks like video editing or gaming at higher resolutions without issue. In fact, software that takes full advantage of multi-core performance will run better on the Ryzen 9 3900X than Intel's Core i9-9900K.

AMD Ryzen 9 3900X

AMD Ryzen 9 3900x (Image credit: Windows Central)

AMD launched the Ryzen 9 3900X to compete with the Intel Core i9-9900K, and while it does perform better in applications that can take advantage of the hyperthreaded 12 cores, the higher frequency the i9 processor can run at, as well as better single-core performance, allows it to pull some blows of its own against Ryzen. In the real world, you won't notice much difference between the two, and that's a good thing for team AMD.

AMD Ryzen 9 3900X offers incredible performance at an affordable price.

The major change with Zen 2 allowing AMD to catch up to Intel is the switch to 7nm manufacturing. Older Ryzen processors were all made on 12nm, while Intel has yet to release processors using a process less than 12nm. Other improvements AMD made with Zen 2 include enhanced bus bandwidth, which essentially allows all the different cores to communicate with one another more efficiently.

There's also PCIe 4.0, which provides additional bandwidth for components like your GPU. Though, in order to enjoy the additional benefits of PCIe 4.0 with Ryzen 3x processors, you'll need one of those pricey AM4 X570 motherboards. Unlike Intel processors, AMD bundles some decent stock coolers with its Ryzen CPUs, and this processor is no different, coming with an AMD Wraith Prism with RGB lighting for synchronization with your favorite motherboard.

Picking the right AMD Ryzen CPU

AMD has a number of product families in the desktop processor market, including the popular Ryzen 3, Ryzen 5, Ryzen 7, Ryzen 9, and Threadripper. But which one is best for you and your PC?

How to pick the right AMD Ryzen CPU

The only area Ryzen 9 3900X struggles with is overclocking, which will require a liquid solution or a far superior aftermarket cooler than what's included with the processor. Overall, the desktop CPU market is more competitive than ever, and it's pushing Intel to do more and offer better value, which can only be good for consumers.

Super-fast but it doesn't beat Intel's Core i9-9900K

AMD Ryzen 9 3900X

Testing the Ryzen 9 3900X, we installed the CPU on the trusty ASUS X470-F GAMING motherboard, joined by a ZOTAC AMP! Extreme GTX 1070 GPU for video output, 32GB of Corsair Vengeance RAM clocked at 3200MHz, and a Samsung EVO Plus NVMe SSD. Our results showed the performance of the Ryzen 9 3900X, but looking at Intel Core i9-9900K — which this AMD chip goes up against — and the numbers are really neck and neck.

For instance, in 64-bit Cinibench, the Ryzen 9 3900X scored 3,027 compared to Intel Core i9-9900K's score of 2,045. It's a similar story in other benchmarks where more cores and threads really give the Ryzen 9 3900X the edge. Gaming is where things start to get even, favoring Intel. The Ryzen 9 3900X often fell behind the Intel Core i9-9900K by between 10 to 20 frames per second (FPS) in a variety of Windows 10 games, but it did fare better in the odd game, including Tomb Raider.

Temperatures were recorded using HWiNFO before, during and after both benchmarks and a stress test. As noted already, temperatures during benchmarks failed to go above 70C (158F), though we did manage to hit 80C (176F) when really stressing the Ryzen processor. Temperature readings were taken using the included stock cooler. You could expect to subtract a good 5-10 degrees off those readings with an AIO or custom water loop.

Instead of just throwing up meaningless numbers around, as mentioned you'll not notice a major difference between the two processors unless gaming is really all you plan to do. If you want to buy the Ryzen 9 3900X, you'll be just as happy as if you purchased the Intel Core i9-9900K. AMD has matched Intel at the same price but threw in four more cores and some neat improvements.

So should you buy the AMD Ryzen 9 3900X?

AMD Ryzen 9 3900X

AMD Ryzen 9 3900X (Image credit: Rich Edmonds / Windows Central)

AMD has done something incredible, even if you do not plan on buying a Ryzen processor. The company has forced Intel to get innovative and think about offering more value to consumers. Should you be looking for a high-end desktop CPU with plenty of cores, threads and performance, you'll be more than satisfied with the Ryzen 9 3900X, especially for the price.

The performance is astounding. Whether you want to play games, do some video editing, or simply want to run some benchmarks and brag to your friends, the Ryzen 9 3900X is an excellent processor, offers great value for the price, and can even outperform an Intel Core i9-9900K in certain scenarios.

Rich Edmonds
Senior Editor, PC Build

Rich Edmonds was formerly a Senior Editor of PC hardware at Windows Central, covering everything related to PC components and NAS. He's been involved in technology for more than a decade and knows a thing or two about the magic inside a PC chassis. You can follow him on Twitter at @RichEdmonds.