AMD Ryzen 9 3900X and Ryzen 7 3700X CPU Review

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Here we are a year and a half after the ZEN+ launch from AMD and we’re finally able to explore their newest CPUs built on the ZEN2 architecture. The new 3000 series Ryzen CPUs are based on the 7 nm Matisse core but also incorporate a 12 nm I/O die (IOD) which can connect one or two core chiplet dies (CCD) for up to 16-cores/32-threads on the mainstream AM4 socket. This is a first in the industry offering HEDT core count and performance at mainstream prices.

The internet has been ripe with rumors and chatter about AMD’s new 7 nm CPUs and today we have the Ryzen 9 3900X 12-core/24-thread and the Ryzen 7 3700X 8-core/16-thread CPUs for testing and we’ll see what these things really can or can not do.

Major Architecture Changes

These changes are aside to the separation of the core and IO/memory controller to separate dies and comparing to the ZEN+ core.

  • 256-bit single-op floating-point (AVX-256) for stronger performance in creative workloads
  • Doubled micro-op cache size to 4K to increase throughput by preventing re-decode of operations
  • New TAGE branch predictor, with larger L1 and L2 BTBs, to increase throughput by reducing stalls from mispredicts
  • A third address generation unit (AGU), which keeps the execution engine more reliably fed with data in DRAM
  • Doubled L3 cache size to 32 MB per CCD, which reduces effective memory latency by up to 33 ns–excellent for games
  • Improved fetch and prefetch capabilities, arming the execution engines more readily with needed data
  • Improved SMT fairness for ALU and AGU schedulers, reducing thread contention and throughput
  • A larger 180-entry register file, providing more immediate access to more working data
  • New hardware mitigation against speculative store bypass (Spectre V4), expanding the strong security profile of ZEN+

Here’s a block-level diagram giving an overview of the ZEN2 core architecture:

AMD’s idea of bringing it all together into one package allows for so much flexibility. You simply add another CCD to increase the core count of the package or possibly even a NAVI based GPU chiplet in the future? Regardless, it gives AMD the opportunity to make monstrous 64-core/128-thread HEDT and server CPUs all based on the same CCDs. Another benefit of using chiplets, is the process allows for better yields and improved density which all amounts to lower consumer costs and likely high profits.

Below we can see a block diagram of a typical two CCD plus IOD package such as the 3900X:

In the DIE shot below you can clearly see the two core dies and the IO die with the Infinity Fabric routings tying it all together.

Specifications and Features

Looking at the specifications table below, we see the new Ryzen CPU is produced using the 7 nm process from TSMC foundries and has 3.9 billion transistors on a 74 mm² die per CCD. There’s also a 12 nm IO/memory controller on the package with 2.09 Billion transistors on a 125 mm² die. AMD is still using solder between the die and IHS on the Ryzen CPUs for improved thermal transfer. Both CPUs are equipped with 32 MB shared L3 Cache per CCD and 512 KB L2 Cache per core.

The Ryzen 9 3900X has a base frequency of 3.5 GHz and a maximum boost of 4.6 GHz with a 105 W TDP. During stress testing, I noticed an all core, heavy load situation, a boost clock which hovered between 4.05GHz and 4.1 GHz.

The Ryzen 7 3700X has a base frequency of 3.6 GHz and a maximum boost of 4.4 GHz with a 65 W TDP. Again I observed fairly high frequencies during stress testing with all cores hovering between 4.05 GHz and 4.1 GHz, slightly higher than the 2700X.

The memory situation with Ryzen has improved steadily as the BIOS matured but it was still a finicky platform. That has all changed now with the changes AMD has made to the controller and how the controller frequency and fabric clock can now decouple. I’ll have more on this later on.

Windows 10 is the officially supported platform for the Ryzen CPUs however it does appear as if Windows 7 installations will again be possible with the right drivers for those still hanging on or competitive benchmarking where every clock cycle available counts.

Specifications below supplied by AMD:

CPU AMD Ryzen 9 3900X AMD Ryzen 7 3700X
# of Cores 12 (2 CCD: 6+6) 8 (1 CCD)
# of Threads 24 16
Base Clock Speed 3.8 GHz 3.6 GHz
Boost Clock Speed 4.6 GHz 4.4 GHz
Instruction Set 64-bit 64-bit
Instruction Set Extensions SSE 4.1/4.2/4a, AES, AVX2, FMA3, SHA
Lithography 12 nm (IOD) and 7 nm (CCD)
Transistor Count 3.9 billion per CCD and 2.09 billion IOD
TDP 105 W 65 W
Thermal Solution Spec Solder
L1 Cache 32 KB I-cache
32 KB D-cache per Core
32 KB I-cache
32 KB D-cache per Core
L2 Cache 6 MB (512 KB per core) 4 MB (512 KB per core)
L3 Cache 64 MB Shared 32 MB Shared
Memory Specifications
Max Memory Size 128 GB 128 GB
Memory Types DDR4-3200 DDR4-3200
# of Memory Channels 2 2
ECC Memory Support yes yes

The table below is a list of the third-generation Ryzen desktop CPU lineup:

Ryzen 9 3950X Ryzen 9 3900X Ryzen 7 3800X Ryzen 7 3700X Ryzen 5 3600X Ryzen 5 3600
MSRP $749 $499 $399 $329 USD $229 USD $199
Silicon 7 nm “Matisse”
Socket AM4
Cores/Threads 16-core/32-thread 12-core/24-thread 8-core/16-thread 6-core/12-thread
Clock Speed 3.5 GHz 3.8 GHz 3.9 GHz 3.6 GHz 3.8 GHz 3.6 GHz
Boost Speed 4.7 GHz 4.6 GHz 4.5 GHz 4.4 GHz 4.4 GHz 4.2 GHz
Cooler Wraith Prism RGB Wraith Prism RGB Wraith Prism RGB Wraith Prism RGB Wraith Spire Wraith Stealth
L2 Cache 512 KB per core
L3 Cache 64 MB shared 32 MB shared
Unlocked Yes
TDP 105 W 65 W 95 W 65 W
Memory Dual-Channel DDR4-2933 JEDEC up to 64 GB
PCIe PCIe Gen 3.0 x16 PEG (x16 or x8 + x8) + x4 M.2 + x4 Chipset
Chipset AMD 400 and 500 Series

Motherboard Support

One of the big questions right now is motherboard support. X570 is the official chipset for Ryzen 3xxx but previous generation support will be in the hands of the motherboard suppliers. The A320 chipset is not going to be supported at all from my understanding, but the rest will likely have support for some of the aforementioned CPUs but not necessarily all with only the robust x370/x470 motherboards offering support for the 12 and 16 core ZEN2 CPUs. Overclocking these monster CPUs on older motherboards will need to be looked at a bit more closely due to the power requirements of these chips when overclocking.

Below is an IO layout of a typical Ryzen 3xxx CPU and the X570 chipset. The blocks labeled as “pick one” are up to the board manufacturer to dedicate functionality.

Energy Efficiency

The 7 nm process has added significant performance, power, and density attributes to Ryzen 3xxx CPUs. Below is a list from AMD calling out key metrics that are directly related to the process change:

  • 29% smaller CCX size vs. 12 nm enabling new area for the Zen2 revisions
  • 75% higher performance per watt compared to 2nd generation Ryzen CPUs
  • 58% higher performance per watt compared 9th generation Intel Core processors based on 14++ nm
  • 2x L3 caches size (32 MB) which wasn’t physically possible on 12 nm
  • Up to 2x the number of cores in the same package (16 up from 8)
  • Up to 350 MHz of core frequency at the same voltage vs. 12 LP

AMD Game Cache

As a direct result of the new 7 nm process, AMD was able to double the L3 cache to 32 MB per CCD. This change has shown a clear benefit in gaming. AMD’s internal testing found that frame rates are up on average of 21% at 1080p and even more so on CPU intensive games or those that use older APIs. Below is a demonstration of memory speed and cache size benefits from AMD testing which clearly shows the benefits of the increased cache size.

Simultaneous Gaming and Streaming

This really isn’t my arena, but I felt it needed to be expressed here so I’ll let AMD do it in their words:

While raw gaming performance is still a common yardstick amongst enthusiasts for performance comparisons, many gamers aspire to even greater heights: streaming their gameplay in high-definition while playing, “Many gamers” is an increasingly astounding figure, too. In the last five years, eSports has grown from a little-known niche corner of the gaming market to a global phenomenon on-track to reach $1 billion in 2019. And the fans are no less enthusiastic, watching 9 billion man hours of content in 2018.

At the heart of this trend lies Twitch, which has helped feed the growth of eSports by serving as a cultural nexus for gamers sharing their gameplay and personalities with loyal fans. But the simplicity of broadcasting to Twitch can come with some steep hardware requirements. According to Twitch customer support, “many broadcasters will find that they get a lot of ‘input lag’ when playing video games.”

“Some games are very CPU-intensive and require a strong computer to run. These games are tough on your processor, especially if you are running the game on the highest settings,” Twitch Support reads.

Broadcasters say the rise of GPU encoding has not done much to address the needs of streamers that expect the best quality for their viewers. Many streamers agree that the relatively tight 3500-6000 Kbps bitrate limits of Twitch, and the short render-to-broadcast window for a smooth stream, put the GPU at a disadvantage. Users often report that GPU encoders need more bitrate to achieve the same quality delivered by a CPU-based x264 encoder preconfigured on streaming packages like QBS and Xsplit. Though GPU encoders are getting better all the time, and work wonders for users on performance-constrained systems, the world’s top streamers still rely on processors or dual systems to give the best result for their fans.

 More recent contenders to the streaming space are acknowledging the growing appetite for higher stream quality, and the expanding portfolio of hardware to deliver it. YouTube, for example, recommends up to 9000 Kbps for live 1080p6O streaming.

But bitrate alone does not determine final quality. It Is widely understood that the x264 encoder profile (e.g. Fast, Faster, Slow] has an outsized impact on the resulting encode, as the CPU spends more or less time on scene analysis before spending bitrate budget on the encode. has been working to address this debate in concrete terms via Netflix machine learning algorithms, which can suss out an exact quality metric by comparing encoded frames to the original. Their results find a bitrate in the range of 7500 Kbps+ with the Slow preset offers the highest quality result on subjective and objective terms with a Netflix VMAF score of 81.9/100—-the best score of any preset they tested.

That brings us to AMD’s own evaluation of gaming and streaming, which we demonstrated privately and publicly using Tom Clancy’s The Division 2, to compare the 12-core AMD Ryzen™ 9 3900X and 8-core Core i9-9900K at approximately the same price. The results were conclusive: the Ryzen 9 3900X can readily handle the higher-quality presets outlined by YouTube and, while the 9900K could not deliver a smooth stream to viewers. Testing across a range of bitrates and titles showed fewer dropped frames in the 9900K stream quality, but dropped frames appear largely unavoidable without sacrificing the high-quality Slow preset. Altogether, this highlights the benefit of newer and more capable hardware, as such devices can accomplish new workloads that are qualitatively beneficial to the user.

Content Creation Leadership

Here again, is another section that’s out of my comfort zone as we don’t have the proper software for testing. AMD with its abundance of cores excels in rendering, encoding, color grading, and more in content creation software such as Black Magic DaVinci Resolve.

 DaVinci Resolve is the world’s first solution that combines professional offline and online editing, color correction, audio postproduction and now visual effects all in one software toot. With a single click, you can instantly move between editing, color, effects, and audio. Plus, you never have to export or translate files between separate software tools because, with DaVinci Resolve 15, everything is in the same software application. DaVinci Resolve is the standard for high end postproduction and is used for finishing more Hollywood feature films, episodic television programing and TV commercials than any other software.

Our test methodology evaluates the time it takes to render out four short RED 8K camera files into four Dolby Vision UHD files in the IMF format.

AMD and Windows 10

AMD, working together with Microsoft have developed two significant features that can be found in the Windows 10 May 2019 update also known as version 1903. Both of the following improvements benefit all Ryzen CPUs not just the new ZEN2 architecture and can be had with the May 2019 update to Windows and a new chipset driver that will be available at launch on July 7th.

Topology Awareness

After the launch of the original Ryzen, there was a lot of chatter about the Windows scheduler not really knowing what to do with all the resources it had available in the ZEN CCX clusters. This was demonstrated to significantly impact performance in some scenarios when the number of cores in the package was increased namely the Threadripper 2990 WX and HCC EPYC CPUs.

Wendel over at Level1 Tech does a great job demonstrating this if you’re interested you can see his YouTube video.

As I said AMD and Microsft got together to help the Windows scheduler allocate workloads more effectively within the Ryzen structure by keeping threads centralized in one CCX before spawning threads into another cluster or another chip on the package improving latency and performance of CPU intensive workloads.

UEFI CPPC2 Interface

CPPC2, or Collaborative Power and Performance Control, is a new way of handling what we have been calling pStates or the different power states of new CPUs which try to balance performance with efficiency. AMD and Microsoft have developed a new clock speed selection method in the UEFI standard aimed at improving latency.

To do this they have moved control over the CPU power to the CPU firmware letting it decide when it needs to speed up and slow down depending on workload. This greatly improves reaction time when performing “burst” type operations like opening web pages or new applications. Typical pState control could take up to 30 ms to perform the power change where the CPPC2 standard improves this up to 30X dropping reaction time to 1-2 ms.

This example was taken from PCMark10 testing done before and after installation of the new AMD chipset driver.


Memory has always been a bit of a thorn in Ryzen’s side, compatibility and speed were very hit and miss. This has improved since the original Zen CPUs hit the market but was still an area that needed attention.

AMD has made some significant changes that need some explaining. Speed and compatibility are no longer an obstacle but that has come with a caveat. Once the memory speed surpasses 3600 MHz the memory bus and infinity fabric “decouple” and operate in a 2:1 ratio, this is automatic. What that means is that the memory could be running at 4000 MHz (2000 MHz real) but the memory controller will be running at 1000 MHz. This causes a jump in latency and a slight performance hit.

The following list comes from the reviewer’s guide and explains what’s going on when the memory is set above 3600 MHz.

  • By default: memory clock (mclk), memory controller clock (uclk), and Infinity Fabric clock (fclk) are fixed in a 1:1:1 ratio until DDR4-3600.
    • Example: DDR4-3200 conveys a 1600MHz memory clock, 1600MHz Infinity Fabric Clock, and 1600MHz memory controller clock.
  • Crossing any speed above DDR4-3600 will automatically enable 2:1 mclk:uclk mode.
    • Fabric Clock will be automatically configured to 1800MHz in 2:1 mode.
    • Example: DDR4-4400 conveys a 2200MHz memory clock, 1800MHz Infinity Fabric clock, and 1100MHz memory controller clock.
    • Users may optionally override the automatic 2:1 mode to maintain a 1:1:1 ratio but will likely find an upper limit as they approach DDR4-3800. This will vary from part to part.
  • Enabling 2:1 mode crosses clock domain boundaries, imparting a DRAM latency penalty of approximately 9ns that may be overcome with additional memory clocks, higher CPU frequencies, or sub-timing adjustments.
  • The Infinity Fabric clock (fclk) always remains freely adjustable in 33MHz steps.

AMD has solved the compatibility issue as well. I tried several different RAM kits from 3200 MHz up to 4266 MHz and all of them just worked once XMP was set in the BIOS. No more guessing and wondering which RAM might work or which RAM IC to have… a breath of fresh air.

While on the topic of RAM I should mention something that popped up while testing the Ryzen 7 3700X CPU. During the AIDA64 Cache & Memory benchmark, I had strange results which troubled me. The write results were approximately half of what I expected. These results can be attributed to many things when testing a new product like this so through a process of elimination the motherboard, BIOS, and AIDA64 itself were ruled out as the cause. I contacted the AMD representative and he forwarded me this response from the AMD team.

“This is an expected result. Client workloads do very little pure writing, so the CCD/IOD link is 32B/cycle while reading and 16B/cycle for writing. This allowed us to save power and area inside the package to spend on other, more beneficial areas for tangible performance benefits.”

In short, the pathway from the chiplet to the memory controller for the write data has been cut in half. This explains why it wasn’t noticeable when testing the Ryzen 9 3900X since it has two pathways to the controller, one from each chiplet so the results appeared normal. It was apparent from all the testing that this decision on the part of AMD had no noticeable effect on expected performance.

Below you can see the difference between the two CPUs:

Ryzen 7 3700X

Ryzen 9 3900X

PCIe 4.0

AMD has taken a position as the industry’s first 7 nm CPU and now added to that with PCIe 4.0. PCI Express 4.0 specification doubles the bus bandwidth of PCI Express 3.0 making 16 GB/s transfer rates possible. It is the way of the future but most users today don’t even saturate a PCIe 3.0 bus.

Product Tour

AMD always sends the best reviewer kits ensuring you have everything you need to do a proper comparison.

The reviewer’s kit included the following:

Ryzen 7 3700X

Ryzen 9 3900X

G.Skill Royal 3600 MHz CL16-16-16
GIGABYTE AORUS PCIe 4.0 2 TB NVMe with copper heat sink installed


All benchmarks were run with the motherboard being set to optimized defaults with XMP setting enabled. I would also like to add that both AMD CPUs were tested with their respective, included Wraith PRISM RGB coolers. All tests were done at the time of this writing with the most recent Windows 10 May 2019 update and the newest updated chipset drivers.

Ryzen 7 2700X  Ryzen 7 3700X  Ryzen 9 3900X i7- 8700K i9- 9900K
Motherboard  ASUS ROG Crosshair VII WiFi  ASUS ROG Crosshair VIII WiFi, MSI MEG X570 Godlike ASUS ROG Maximus APEX X
 Memory G.Skill FlareX 2×8 GB DDR4-3200 MHz 14-14-14-34
 Graphics Card RADEON RX 5700 XT
 HDD Toshiba OCZ 480 GB TR200 SSD
 Game Storage Samsung T5 1 TB Portable SSD
 Power Supply EVGA 750 W G3
 Cooling  EVGA CLC 240  AMD Wraith Prism RGB  EVGA CLC 240
 OS  Windows 10 x64

Benchmarks Used

CPU Tests
  • AIDA64 Engineer CPU, FPU, and Memory Tests
  • Cinebench R20 and R15
  • HWBot x265 1080p Benchmark
  • POVRay
  • SuperPi 1M/32M
  • WPrime 32M/1024M
  • 7Zip

All CPU tests were run at their default settings with XMP enabled unless otherwise noted.

Gaming Tests

All game tests were run at 1920×1080p with all CPUs at defaults. Please see our testing procedures for details on in-game settings.

  • 3DMark Fire Strike Extreme
  • F1 2018
  • Far Cry 5
  • Ashes of the Singularity: Escalation
  • Shadow of the Tomb Raider

AIDA64 Tests

Just a note here, I used the latest AIDA64 Engineer Beta for testing and the team at AIDA have replaced some of the benchmarks we have used in previous reviews in favor of some newly updated benchmarks. New this time around is the SHA3 test in the CPU portion and FP-64 ray tracing in the FPU section.

AIDA64 Cache and Memory Benchmark
CPU Read Write Copy Latency
Ryzen 7 2700X  48976 47771 43179 65.9
Ryzen 7 3700X 46665 25551 44440 72.4
Ryzen 9 3900X 49035 47403 50265 72.7
Intel i7-8700K 47015 46129 42329 43.4
Intel i9-9900K 47792 46991 43394 42.1

As you can see the Ryzen CPUs do well in the bandwidth tests with one outlier the 3700X in the Write test. This was covered earlier on in the memory portion of the features section. It also appears as though there has been another slight increase in latency compared to the Ryzen 7 2700X, likely a result of the core and IO separation. Up next the AIDA64 CPU benchmarks.

AIDA64 CPU Tests
CPU Queen PhotoWorx Zlib AES SHA3
Ryzen 7 2700X  94744 25704 768 71513 2288
Ryzen 7 3700X  99389 20956 844.5 74598 2463
Ryzen 9 3900X 124533 23909 1199 106707 3546
Intel i7-8700K 72531 25755 578 29412 2530
Intel i9-9900K 101020 24851 837 42873 3688

The CPU tests show the Ryzen 7 3700X is holding up well compared to the i9-9900k despite a speed disadvantage. The Ryzen 9 3900X was quite dominant throughout all the testing in both sets of AIDA64 benchmarks because of its 12-core/24-thread advantage.

AIDA64 FPU Tests
CPU FP64-RT Julia Mandel SinJulia
Ryzen 7 2700X 4289 41738 21811 13766
Ryzen 7 3700X 8444 79410 41905 14485
Ryzen9 3900X 12153 115410 61164 20707
Intel i7-8700K 6170 54910 28236 7785
Intel i9-9900K 8841 78610 40110 11347

The floating-point tests no longer appear to be a weak spot for the new Ryzen 3xxx CPUs. AMD did a lot of work in this area and it looks like it really paid off. Of course, the 3900X dominated once again but the 8-core results are much more telling. Comparing the 2700X to the 3700X we can see the scores nearly doubled across all the tests aside from SinJulia. The most interesting part here despite the core speed advantage the 9900k was left behind in nearly all tests

Real World Tests

Next, we will move on to something a bit more tangible/productivity-based with compression, rendering, and encoding benchmarks.

Cinebench R20/R15, POVRay, x265 (HWBot), 7Zip – Raw Data
CPU R20 R15 POVRay x265 7Zip
Ryzen 7 2700X  4064 1807 3696 45.14 67515
Ryzen 7 3700X  4842 2112 4317 64.44 80416
Ryzen 9 3900X  6952 3073 6097 81.1 108758
Intel i7-8700K 3402 1404 2951 47.68 54266
Intel i9-9900K 4467 2023 3888 64.84 72185

Here again, the extra threads gave the Ryzen 9 3900X a big advantage over the other CPUs in all benchmarks. The improvements to the ZEN2 architecture are quite noticeable when comparing to the last generation and places the 3700X above the 9900K in all tests save the X265 benchmark where they were practically tied.

Pi-Based Tests

Moving on from all the multi-threaded goodness above, we get to some Pi and Prime number based tests. SuperPi and WPrime, specifically.

SuperPi and wPrime Benchmarks – Raw Data
CPU SuperPi 1M SuperPi 32M wPrime 32M wPrime 1024M
Ryzen 7 2700X 9.87 547.348 3.36 85.22
Ryzen 7 3700X 9.422 529.083 2.746 71.941
Ryzen 9 3900X 9.094 516.084 2.328 50.363
Intel i7-8700K 7.952 453.632 3.468 100.713
Intel i9-9900K 7.514 412.387 2.58 76.168

This time Intel pulled ahead in the Super Pi tests, partly due to their much higher single-core boost speeds but this has always been a good benchmark for Intel even when at the same clock speed.

WPrime, on the other hand, is more sensitive to core count and this easily shows in the results with the new AMD CPUs pulling ahead again.

Game Results

As far as the games go, tests were done at 1920 x 1080p according to our Graphics Testing Procedure which was linked earlier. The CPUs are all at defaults with the 3200 MHz FlareX set to XMP to give a better display of real-world results.

As you can see above in the gaming results, AMD has made some nice improvements over the last generation of Ryzen CPUs. The results are pretty tight across the board except for Far Cry 5 but it doesn’t appear that Intel can claim the gaming crown any longer! At this point, users will find little difference between the two CPUs in most titles.

On to the synthetic benchmark, 3DMark Fire Strike, you can see the results are very close across the board except for the Physics test. The interesting part is the graphics results with every CPU producing nearly identical results.

IPC and SMT/HT Comparison

For our IPC testing, all cores and threads were set to 4 GHz. Setting the CPUs this way and testing using single-threaded benchmarks will allow us to see the difference.

AMD held true and did improve the IPC (Instructions per Clock) of the third-generation Ryzen CPUs. Comparing the 2700x to the 1700x in this limited amount of testing averages out to 3.15% which is right where AMD placed it. Comparing Ryzen+ to the competition puts them slightly behind the 8700K but not by much and these numbers do not include SMT, which, when compared to Intel’s HT is more efficient in most scenarios as you’ll see below.

Zen 2, depending on the test, is beating out the Intel offering by several percent in Cinebench and POVRay, though compression using 7Zip, Intel still seems to perform marginally better there.

The chart below compares AMD’s SMT efficiency to Intel’s HT as well as the previous generation of Ryzen. The results speak for themselves really, AMD is way ahead in all tests. This time with the front end improvements they even pulled ahead of Intel in the 7-Zip test where they were lacking a bit in the previous generation.

Power Consumption and Temperatures

In the graph below we tested power use of the system across multiple situations from idle, to Prime 95 Small FFT (with FMA3/AVX). The 3900X  pulled the most power during the AIDA64 FPU test with 220 W. What’s interesting,  that’s 5 W lower than the 2700X in our previous testing despite adding 50% more cores. This really shows the benefits of the 7 nm process and AMD’s efficiency. The 3700X seemed to pull the same power from the wall in all tests at a steady 160 W (we are not sure why at this point and will update this section as information comes in). Keep in mind this is full-system power usage.

Temperatures were surprisingly well-controlled with the included Wraith Prism RGB coolers, I saw no throttling at any point. The highest temperature was 75 °C with the Ryzen 9 3900X during Prime95 Small FFT. This shows that the stock cooler is adequate for the 3900X at stock settings. For the Ryzen 7 3700X, the Wraith Prism RGB kept it at 66 °C during P95 small FFT testing. These results are well below Ryzen’s maximum temperature of 95°C.

Pushing the Limits

Now the moment you’ve all been waiting for, “so how fast will they go?” I switched over to my EKWB Predator 360 XLC closed-loop cooler for improved cooling which took me up to 4.35 GHz and stable on both the Ryzen 7 3700X with 1.45 V and the Ryzen 9 3900X with 1.4 V. This seems to be the limit for both of these samples on good ambient cooling. I tried going higher with additional voltage but Cinebench R20, which is a very, very demanding benchmark would cause a black screen and system reboot.

Ryzen 7 3700X 4.35 GHz 1.45 V 3600 memory CL16
Ryzen 7 3700X 4.35 GHz 1.45 V 3600 memory CL16

As you can see above the Ryzen 7 3700X made some gains across the board in all of the benchmarks and ran relatively cool with the 360 CLC even though we were at 1.45 V which is about as high as anyone should go.

Ryzen 9 3900X 4.35 GHz 1.4 V 3600 memory CL16
Ryzen 9 3900X 4.35 GHz 1.4 V 3600 memory CL16

The same goes for the Ryzen 9 3900X, there were gains to be had with overclocking which were even more significant than the 3700X. A shot of Ryzen master was included with this Prime95 test just to have a comparison with HWInfo for accuracy of the temperature readings.

X470 Compatibility

Just before the embargo was lifted ASUS posted a BIOS for the ROG Crosshair VII Wifi. I had tested a previous release but it didn’t function quite right. After downloading ver. 2406 and using the flashback function of the motherboard I came up with some results. These are slightly higher than the results posted in the testing portion of this review but that would be due to improved cooling and precision boost taking advantage of that. Below is a sample of benchmarks which were run on the Crosshair VII using the 12-core 3900X just to demonstrate that these CPUs will work from day one on older hardware.

ASUS ROG Crosshair VII Hero WiFi, Ryzen 9 3900X, G.Skill FlareX 3200 MHz CL14

Memory Penalty

As was mentioned, compatibility with higher speed memory was as easy as enabling XMP and 4000 MHz CL17 booted right up without a hiccup. Just to demonstrate the latency penalty two instances of Cinebench R20 were run at the same static CPU speed. One instance (on the left) was using 3600 MHz CL16 memory and the controller is running 1:1. The picture on the right is using 4000 MHz memory and this is where the controller and Infinity Fabric “de-couple” so the controller is running at half speed. You can see it as the NB reading in CPUz.

3600 MHz CL 16

4000 MHz CL17

CPUz NB at half speed

As you can see there is a slight performance penalty which would depend on the application. Higher RAM speed increases the bandwidth which can be important to some software but on the ZEN2 CPUs it also increases latency.

Windows 7

I was able to successfully install Windows 7 X64 on the X470 platform. My media wouldn’t work for X570 which leads me to believe that there have been some driver changes but due to a lack of time I haven’t been able to update my installation media. Below is a screenshot of Windows 7 on a Crosshair VII with the Ryzen 9 3900X CPU.


Both CPUs behaved nearly identical when it came to voltage requirements. They were both stable at 4.35 GHz, the 3900X needed slightly less voltage at 1.4 V where the 3700X needed just a touch more up to 1.45 V. The happy medium was found to be 4.2 GHz where they would both run stable and cool with only 1.25V and just like the previous generations the voltage scaled quickly as the frequency went up from there. Anyone familiar with the Ryzen platform will also know about the V-Droop associated with it. On both motherboards, ASUS and MSI the voltage seen in Windows was the voltage set in BIOS there wasn’t any need to modify the LLC settings.

Overall, the performance of AMD’s third-generation Ryzen CPU is quite impressive, leveraging higher clock speeds and efficiency from the 7 nm process improvements. To me, it appears as if they have accomplished all their goals. Overall speed has increased slightly over the previous generation. There has definitely been an improvement in the front end and doubled L3 Cache has big benefits of its own. This is quite apparent by the boost the new Ryzen has gotten in tests such as 7Zip and even more so in the gaming tests where we saw roughly on par performance when compared to the 9900K. The RAM situation has also improved, every kit tested on XMP easily booted into windows. There is one caveat, as was demonstrated above, that going above 3600 MHz does incur a slight latency penalty.

AMD has delivered on their promises for ZEN2, it does run faster and more efficiently showing some nice improvements on the ZEN microarchitecture. The new Ryzen CPU should be widely available by the time anyone is reading this review. Currently, the Ryzen 9 3900X should be listed at $499.99 and the Ryzen 7 3700X will be available for $329.99. Pricing for the full line-up was listed above in the specifications section. Comparing these prices to the Intel i7-8700K at $364.99 makes eight-cores for less than the price of six an attractive offer which has always been another one of AMD’s strong points. Or how about 12-cores and 24 threads for the same price as the 8-core/16-thread i9 9900k? For heavier users in video and media creation, this is a great price for 50% more work.

A bit more overclocking headroom and improved performance, plus an improved IPC which surpasses current Intel offerings and leverages additional performance at stock settings. Pairing these with an improved 500-series chipset which brings in the new standard of PCI express 4.0 makes the Ryzen 3000 series CPUs very competitive. One added bonus is that the days of memory compatibility issues are gone offering the end-user a rewarding, stress-free experience. A big thumbs up and Overclockers Approved!

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Shawn Jennings – Johan45

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  1. bmwbaxter
    For once the hype was real! Great review, do you think the 4.2GHz @1.25V would be doable on the stock cooler?

    Yep, temps weren't too bad and they perform very well just leaving them at stock with the PBO engaged
    Now that the NDA is gone, any chance of some testing on b450/x470 boards and with more/different memory sticks?
    I assume any testing was limited to the reviewer kit only, which limited you to x570 boards and 2x8gb 3200 ram.
    Now that the NDA is gone, any chance of some testing on b450/x470 boards and with more/different memory sticks?
    I assume any testing was limited to the reviewer kit only, which limited you to x570 boards and 2x8gb 3200 ram.

    I did test the CHVII X40 with 3600 which booted at XMP but they still need some BIOS work done. The bus decoupled at that speed and when I dropped it to 3533 it's not supposed to do that until after 3600 MHz. The memory compatibility is in the new CPU more so than the motherboard it's in.
    EDIT: I just installed 4000 CL17 and it booted with 18-17-17 timings, looks like geardown is still a thing but I'm running a quick GB4 to post here then heading out for a bit.
    As you can see even though the memory is at 4000 I scored slightly lower than at 3200
    Now that the NDA is gone, any chance of some testing on b450/x470 boards and with more/different memory sticks?
    I assume any testing was limited to the reviewer kit only, which limited you to x570 boards and 2x8gb 3200 ram.
    There is a section in our review on that....check it out...
    As always outstanding review. I now feel confident upgrading to a 3700x. Thank you sir!
    I found on reddit an AMD review megathread so I linked you reviews both Matisse and NAVI reviews and the OP has since added OCFs links.
    As always outstanding review. I now feel confident upgrading to a 3700x. Thank you sir!
    I found on reddit an AMD review megathread so I linked you reviews both Matisse and NAVI reviews and the OP has since added OCFs links.

    Thanks Blay, I used to post that to /r/hardware as well but got yelled at by mods for posting from the same source a lot (sigh). If someone else can do that I'd appreciate it.
    If I had to guess... I wouldnt hold my breath. We didnt get much if any better OC out of a new bios. Nothing will make these 5 GHz chips... 4.5 ghz chips I dont think either... :(
    any idea if there any bios fix coming for overclocking , or this CPU is doomed for almost no OC ?

    Maybe as the process matures a bit we'll see another bump in speed but no these are never going to OC well
    If I had to guess... I wouldnt hold my breath. We didnt get much if any better OC out of a new bios. Nothing will make these 5 GHz chips... 4.5 ghz chips I dont think either... :(

    too bad then , processor with almost 0 overclocking , should not be welcome in this forum :-)
    Maybe as the process matures a bit we'll see another bump in speed but no these are never going to OC well

    i will stick with Intel then , most i hate is poor overclocking cpu