AMD Ryzen 9 3900X review

Team Red’s takeover

AMD Ryzen 9 3900X
Best in Class
AMD Ryzen 9 3900X

Our Verdict

The AMD Ryzen 9 3900X is the best mainstream processor on the market right now. With multi-threaded performance that destroys everything in its path and the inclusion of PCIe 4.0, you can’t find a better processor without stepping up to the HEDT market.

For

  • Incredible performance
  • PCIe 4.0
  • Beats Intel at same price

Against

  • Included heatsink may not be enough
  • Single core performance still behind

In our mind, the best processors are the ones that deliver killer performance at a price point that makes sense. The Ryzen 9 3900X absolutely nails this concept.

This processor packs 12-cores and 24-threads in a mainstream package for the first time, and does it at around the same price point as the Intel Core i9-9900K, a processor with just 8-cores and 16-threads.

The AMD Ryzen 9 3900X marks yet another blow from Team Red, ramping up the intensity of the AMD vs Intel processor war. Still, though, core counts aren’t everything when it comes to a mainstream processor, as single-core performance needs to be on point, especially if you plan to use it to play the best PC games

So, the big question here is going to be “does the AMD Ryzen 9 3900X dethrone the Intel Core i9-9900K as the best mainstream processor?” The answer is ultimately “it depends,” as it doesn’t reach the same single-core performance as Intel, but as more games adopt multi-threaded workloads, the answer to that question gets a little more complicated.

AMD Ryzen 9 3900X unpacked

AMD Ryzen 9 3900X unpacked

(Image credit: Future)

Price and availability

Speaking of which, if you want to get a high-end desktop (HEDT) 12-core processor that can keep up with the AMD Ryzen 9 3900X, you’re going to have to spend significantly more money and get something like the $1,189 (£1,329, AU$1,799) Intel Core i9-9920X. Even if you do go with this Intel Basin Falls Refresh chip, you won’t necessarily get the same level of performance.

The AMD Ryzen 9 3900X is available now for $499 (about £390, AU$720). This is actually a great price point, as it goes right up against the $488 (£498, AU$777) Intel Core i9-9900K while offering an extra four cores. It doesn’t boost as high, and the retail box isn’t as cool, but any creatives that are looking for a great processor without jumping for a Threadripper 2nd Generation chip should take notice. 

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Features and chipset

AMD Ryzen 3rd Generation, and the Zen 2 architecture itself, is notable because it brings 7nm processors to the mainstream for the first time. But, there’s a lot more going on under the surface than a smaller manufacturing node. 

The most important improvement, and the easiest to digest, is the massive boost to IPC, or instructions per clock. AMD claims that it was able to increase IPCs in its 3rd generation Ryzen chips by up to 15%, which goes a long way to explaining why single-core performance sees such a boost over something like the AMD Ryzen 7 2700X

That increased IPC improvements, along with the massive turbo boost of 4.6GHz mean that even in single core performance – long a weak point of AMD’s processors – comes within reaching distance of Team Blue’s chips. 

One thing that the move to 7nm silicon has allowed for however, is an increase in cache size. AMD is now labeling its L3 and L2 cache in a combined spec of ‘GameCache’ – though functionally it’s the same thing. But, because the 7nm CPU cores are contained within their own chiplets, AMD was able to pack much more in – with a whopping 64MB of L3 and 6MB of L2, for a combined 70MB of GameCache. This is a big deal, as it allows for much faster performance, especially when you’re shooting for high framerates in 1080p games, and will be especially effective in old esports titles like Counter Strike: Global Offensive. 

Another improvement that AMD Ryzen, and more specifically the X570 chipset, brings to the table is the long-awaited inclusion of PCIe Gen 4. Now, the only graphics cards that use PCIe 4.0 today are the AMD Radeon RX 5700 XT and AMD Radeon RX 5700, but your GPU is almost less noteworthy than the improvements it will bring to the best SSDs

We were given a Aorus PCIe 4.0 SSD to test, and the speeds we see are mind-blowing. We were able to get sequential reads of 4,996 MB/s, a 29% boost over our previous fastest SSD, the Samsung 970 Pro. Out of all the features that Ryzen 3rd Generation brings to the table with the new X570 chipset, this might be one of the most impactful – and also explains why there are so many high-end AMD motherboards this time around. 

Finally, the shrink down to 7nm allows for much better energy efficiency. Thanks to the Zen 2 architecture, AMD Ryzen 3rd Generation processors like the Ryzen 9 3900X should be up to 58% more efficient than comparable Intel processors. This isn’t the most attention grabbing feature here, but, hey, it should translate to lower electricity bills, and in today’s economy every little bit helps, right?

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Test system specs

CPU: 3.8Ghz AMD Ryzen 9 3900X (12-core, 70MB cache, up to 4.6GHz)
GPU: Nvidia GeForce GTX 1080 Ti
RAM: 16GB G.Skill Royale DDR4 (3,400MHz)
Motherboard: ASRock Taichi X570
Power Supply: Corsair RM850x
Storage: 2TB Gigabyte Aorus M.2 SSD (NVMe PCIe 4.0 x4) Case: Corsair Crystal Series 570X RGB
Operating system: Windows 10

Performance

It shouldn’t be too terribly surprising that a 12-core, 24-thread processor with a 4.6GHz boost clock is an absolute beast when it comes to performance. The AMD Ryzen 9 3900X is straight up the fastest piece of silicon you can buy without wading into the HEDT scene – at least until the Ryzen 9 3950X comes out in September 2019. 

The AMD Ryzen 9 3900X especially shines when it comes to multi-threaded workloads. For instance, in both Geekbench and Cinebench R15, the 12-core processor scored a whopping 44,160 and 3,097, respectively. Compared to the Intel Core i9-9900K, which scores 33,173 and 1,873 in the same tests, it’s a night and day difference. For about the same price point, the Ryzen 9 3900X is between 25%-40% faster than the Intel Core i9-9900K in multi-threaded loads.

Unfortunately, this doesn’t quite translate to single-core performance, even if AMD is closer than it’s ever been to matching Intel core for core. In our single-core GeekBench and Cinebench tests, the Ryzen 9 3900X scored a 5,569 and 203, respectively. This is definitely a huge improvement over the Ryzen 7 2700X, but it’s slower than the 9900K, which scored a 6,333 and 211 in the same tests. But, that’s still between a 4% and 13%, so the multi-core gains generally outweigh them. 

And, when it comes to gaming, the general rule of thumb for about as long as we could remember is that single-core performance is king. However, in a lot of modern games – likely due to the prominence AMD Ryzen processors have gained – multi-core performance is becoming more and more important. For instance, in Total War: Warhammer II, we were seeing higher frame rates at 1080p with the 3900X than with the Intel Core i9-9900K with the same Nvidia GeForce GTX 1080 Ti GPU – up to 17%, in fact. 

The big downside here, though, is power consumption and thermal performance. Now, we should be abundantly clear here: we tested using the included Wraith Spire cooler, rather than using an AIO liquid cooling solution. Still, we saw temperatures peak at 83 degrees Celsius, and power consumption go all the way up to 145W. So, while the included thermal solution will do in a pinch, we recommend picking up an aftermarket cooler – something potential customers for a chip of this caliber will probably do anyways.

AMD Ryzen 9 3900X in Aorus X570 Max motherboard

AMD Ryzen 9 3900X in Aorus X570 Max motherboard

(Image credit: Future)

Final verdict

The AMD Ryzen 9 3900X is an absolute beast of a processor, which it absolutely should be with its core count and high price tag. If you’re looking for the absolute best processor money can buy on a mainstream processor, look no further. Whether you’re playing PC games or even doing hardcore video and 3D work, the AMD Ryzen 9 3900X is an absolute unit of a chip.

However, you should be aware that there are some workloads where the Intel Core i9-9900K will still excel in. Old games that are completely single threaded, like World of Warcraft, will still do better on an Intel processor – but that gap is definitely starting to narrow.

The inclusion of PCIe Gen 4.0 is also a huge benefit to choosing the Ryzen 9 3900X, as it should contribute to a faster system overall, thanks to speedier SSDs – and that’s something you can only get with Ryzen 3000 and X570. Over the last couple years, AMD has been reaching for dominance in the desktop CPU world, and with the Ryzen 9 3900X, it's finally there.