AMD Ryzen 9 3900X Review 170

AMD Ryzen 9 3900X Review

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Value and Conclusion

  • The AMD Ryzen 9 3900X retails for $500.
  • 12-Cores, 24-Threads in a desktop platform!
  • Beats Core i9-9900K conclusively in multi-threaded applications
  • Gaming performance significantly improved, 10% over previous generation
  • Outstanding multi-threaded power efficiency
  • Unlocked multiplier
  • Supports existing AM4 motherboards
  • Much bigger L3 cache, lots of other architectural improvements
  • Improved memory support
  • Heatsink included
  • Support for PCI-Express 4.0
  • Still not as fast as Intel in gaming
  • No integrated graphics
AMD's new Zen 2 family of processors starts a new era in CPU technology by introducing the chiplet design made up of several optimized pieces of silicon that are designed to excel at their tasks, while reducing cost significantly at the same time. Instead of a large monolithic die, AMD broke their CPU up into multiple parts that are easier and cheaper to manufacture because of their smaller die size. In silicon manufacturing, a bigger die is harder to make because chances of randomly distributed defects ending up in your silicon go up the bigger the die. AMD was also wise to keep the I/O controller die on the 12 nanometer process because it doesn't benefit from 7 nanometer tech, and they can continue using GlobalFoundries for that instead of the more expensive TSMC fabs.

Ryzen 9 3900X is the most powerful AMD processor launching today. It features an amazing 12 cores and 24 threads, which is unheard of in a mainstream desktop platform. I'm sure Intel would still be selling up overpriced quad-core processors if it weren't for AMD Ryzen. Later this year, AMD will even release the 16-core / 32-thread Ryzen 9 3950X, which will work on the same AM4 platform, too. Looking at our performance testing, we see the Ryzen 9 3900X beat Intel's Core i9-9900K in applications with a 13% lead. Our mix of applications includes tests that are highly threaded, somewhat threaded, and single threaded. If you focus only on higher-threaded applications, that lead would be even bigger. Still, the Ryzen 9 3900X does fall behind a bit in single-threaded application, like Microsoft Office and Adobe Photoshop, because Intel still has the higher single-threaded performance, mostly thanks to their much higher boost clock speeds on premium parts.

When looking at gaming, our results confirm that AMD has caught up big time here, too, and the performance differences are much smaller. At higher resolutions like 1440p and 4K, the gap is pretty much non-existent, and parity with Intel has been reached. However, you probably don't even need such a fast CPU for gaming at these resolutions as even the Intel Core i5 processors deliver almost identical frame rates here. I expect the same will be true for AMD's Ryzen 5 3600/3600X we'll be reviewing very soon. The king of the hill for gaming performance is still the Core i9-9900K, though, and this becomes apparent at the resolution of 720p, which completely removes the GPU bottleneck and puts CPU performance under a microscope. Here, both the Intel Core i7-9700K and Core i9-9900 have a lead of about 10%, though pretty much only because their processors run at higher clock frequencies.

Overclocking the Ryzen 9 3900X proved difficult because its heat output is so high. Even with a 240 mm all-in-one water cooler, we couldn't even get close to what it can do. We had to lower our voltage over and over again to keep it from overheating when fully loaded on all cores. In the end, our maximum overclock of 4 GHz is disappointing compared to what (low-threaded) boosts we would see from even the stock processor. Of course, if you run highly threaded applications all day and the CPU is 100% loaded, manual overclocking can provide some benefits, but for everybody else, it simply makes most sense to overclock using PBO, which keeps the heat output low enough for the stock heatsink to handle it, and it also provides the much needed boost clocks for low-threaded workloads.

A reworked memory subsystem not only improves compatibility with various memory vendors, but also helps overclockers because memory speeds above DDR4-3600 are now in reach. We tested this in a separate article today and can confirm that DDR4-4000 was not any more difficult than on Intel. Overclocking and tweaking is vastly simplified by AMD's Ryzen Master software, which in its latest iteration is better than ever, saving you from having to go into the BIOS all the time.

Power efficiency of Zen 2 is good, definitely improved over previous generations, probably due to the 7 nanometer production process. What caught our attention was multi-threaded energy usage, which measures how much total energy is used to complete a specific task—it takes into account not only power draw, but also time required to complete an operation. Here, the Ryzen 9 3900X claims the top spot as the most energy-efficient processor we have ever tested. Temperatures are a bit high, though, with 79°C, but all the performance has to come from somewhere.

Priced at $500, the Ryzen 9 3900X goes up right against the Intel Core i9-9900K that's priced similarly. Unlike the Intel processor, AMD was kind enough to include a heatsink with their processor, so you can get your new rig set up immediately. This included heatsink is not some cheap, low-quality heatsink, but a decent cooler. Congratulations, AMD!
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