AMD Ryzen 9 3900X vs Intel Core i9-9900K: Which High-end CPU Should You Buy?

In this post, we compare Intel and AMD’s flagship desktop processors, the Ryzen 9 3900X and the Core i9-9900K and see which one is faster Although technically the AMD Ryzen 9 3950X is the fastest consumer CPU, we won’t be considering it as it mostly squares off in the HEDT space, against the Cascade Lake-X parts.

We will be putting AMD and Intel’s fastest desktop chips through their paces and analyze how they perform across a variety of workloads from gaming to content creation as well day-to-day tasks like file-compression and video encoding.

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

Ryzen 9 3900X Core i9-9900K
Cores/Threads 12/24 8/16
Base Clock 3.8GHz 3.6GHz
Boost Clock 4.6GHz 5GHz
L2 Cache 6MB 2MB
L3 Cache 64MB 12MB
TDP 105W 95W
Price $400 $480

On paper, the Ryzen 9 has the Core i9-9900K beat on all fronts except the boost clock. Looking at the TDP, it may seem like the latter is more power-efficient but that’s far from the truth. The 9900K draws nearly 200W under load while the 3900X doesn’t cross the 120W mark in most cases. Furthermore, the pricing makes it even harder to recommend the Core i9. Recently, AMD’s Ryzen 3000 CPUs have seen some steep price drops, bringing the Ryzen 9 down to $400 (from $500). The 9900K still retails for a hefty $550 ($480 on Microcenter). You can snag the KF variant for less than $500 if you plan on using a discrete GPU.

Test Bench


  • ASRock X570 Taichi (AMD)
  • Gigabyte Z390 Aorus Master (Intel)


  • G.Skill Trident Z Royal 8GB x 2 @ 3600MHz

Graphics Card:

  • NVIDIA GeForce RTX 2080 Ti


  • WB Black 480GB M.2 SATA
  • WD Black 4TB HDD


  • Corsair HX1000i

AMD Ryzen 9 3900X vs Intel Core i9-9900K: Gaming Performance

In gaming, the Intel Core i9-9900K is faster by around 10-15% on average. Although certain games like Assassins’ Creed and Ashes of the Singularity (not included above) are known favor the higher core count of the Ryzen 9, they’re part of the minority. The conclusion here is that in terms of gaming performance, Intel still has a clear lead in the ultra-high-end segment.

Content Creation

Surprisingly in the single-threaded Cinebench R20 test, the Ryzen 9 3900X manages to edge past the Core i9-9900K despite having a lower boost clock. This means that the deficit in gaming may be due to the latency induced by the Infinity Fabric, rather than the IPC.

The multi-threaded benchmark goes as expected. The 3900X and its 24 threads impose a heavy lead over the 9900K. The former is almost 50% faster than the Coffee Lake flagship. For the sake of comparison, the 1st Gen Threadripper with its 32 threads scores just above 6,500 points. That’s notably lesser than the 3rd Gen Ryzen 9 3900X. AMD really has come a long way in the last two years.

The delta only widens in IndigoBench, with the Ryzen 9 increasing its lead over the 9900K to a staggering 75%. For content creators and professionals, the 3rd Gen Ryzen lineup is a dream come true. A $400 chip performing on par with a $1,000 part is nothing short of phenomenal.

Encoding, Browsing, and Compression

Compression/decompression, web-browsing, and encoding applications are used on a large scale by just about everyone. We consider these as a measure of day-to-day or real-world performance. In 7-zip (both compression and decompression), the Ryzen 9 squishes the Core i9 by a fat margin. The deltas in Handbrake x264 and Kraken (browsing) are less pronounced but nevertheless, mark a resounding victory for the Ryzen 9.


Overall, the Ryzen 9 3900X is the undoubted performance king. Offering 90% of the gaming performance as the Core i9-9900K and being more than 50% faster in everything else, the 3900X is the clear winner here. However, which chip you should opt for largely depends on your workloads. If you are building a gaming PC that will be used exclusively for high frame-rate gaming, then the Core i9 is a no-brainer. However, if you’re a content creator or your workloads are more versatile than just gaming, then the Ryzen 9 3900X is the sensible choice.


Computer hardware enthusiast, PC gamer, and almost an engineer. Former co-founder of Techquila (2017-2019), a fairly successful tech outlet. Been working on Hardware Times since 2019, an outlet dedicated to computer hardware and its applications.
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