AMD Ryzen 7 3700X & Ryzen 9 3900X review

Processors 196 Page 2 of 28 Published by


Ryzen 3000 processor family

The Ryzen Generation 3 (Matisse) processors

Early this year, AMD has been making a series of announcements on their processor platform, several procs, and the new X570 chipset. We’ll first walk through all that new kit to get you an idea of what’s being released and, of course, talk a bit more about the chiplet design and what that is all about. Meet the processors that are going to be injected into the market over the months to follow:

  • 16-core Ryzen 9 3950X will be priced 749 USD (September 2019)
  • 12-core Ryzen 9 3900X will be priced 499 USD
  • 8-core Ryzen 7 3800X will be priced 399 USD
  • 8-core Ryzen 7 3700X will be priced 329 USD
  • 6-core Ryzen 5 3600X will be priced 249 USD
  • 6-core Ryzen 5 3600 will be priced 199 USD

AMD announced six Ryzen 3000 processors with a spread of six to sixteen core products. Ryzen 3600(X) with six cores and twelve threads, 3700(X) (8t/16t), 3800X (8c/16t) And Ryzen 9 3900X (12c/24t). And that means silicon with two 8-core CPU dies immediately enters the market. AMD promises IPC increases of almost 15% and even 25% when you add the increase in clock frequency. Most Ryzen models will get Turbo bins towards 4.4~4.6 GHz. AMD also announced one flagship processor, the Ryzen 9 3950X, a sixteen core part with thirty-two threads and a Turbo binning towards 4.7 GHz. 


Ryzen 3000 - Zen Generation 3 die - with 12 or 6 cores it has two 7nm CPU dies, the big one in the middle is the IO chiplet. Combined these are called a chiplet design.


Cores / Threads

Clock speed/turbo (GHz)

Cache (total)

PCIe lanes 
CPU+x570 chiplet)


Ryzen 9 3950X


3.5 / 4.7



$ 749 

Ryzen 9 3900X


3.8 / 4.6



$ 499

Ryzen 7 3800X


3.9 / 4.5



$ 399

Ryzen 7 3700X


3.6 / 4.4



$ 329

Ryzen 5 3600X


3.8 / 4.4



$ 249

Ryzen 5 3600


3.6 / 4.2



$ 199

Let's walk through the procs for a minute. AMD has announced new 6, 8, 12 and 16-core processors for its 3rd gen, 7nm fabbed CPUs. The Ryzen 9 3950X is the all-new sixteen core part (due for release/availability in September). The new flagship consumer processor will have 16 cores and 32 threads with a massive 4.7 GHz Boost, its base frequency sits at 3.5 GHz though, but it has no less than 72MB cache, AMD is keeping the power consumption under control at 105 Watts (!).

Ryzen 9 3900X will have 12 cores and 24 threads with a 4.6 GHz Boost, its base frequency sits at 3.8 GHz, AMD is keeping the power consumption in check, also at 105 Watts. AMD sees this proc as a competitor for the Core i9 9920X. 

Next in line is probably what will attract the PC gaming community best, a spicy eight-core processor with sixteen threads, the Ryzen 7 3800X. This processor may boost to 4.5 GHz and gets a 3.9 GHz base clock frequency. It has 36 MB total cache and is the proc that AMD pits against the Core i9 9900K. This proc is also listed as having a 105 Watt TDP. 

At 329 USD the Ryzen 7 3700X might be the new moneymaker and bestseller as it offers that really nice balance between features, perf, and pricing. This processor also has 8 cores, 16 threads but only runs 100 MHz less on the boost frequency. With a 3.6 GHz base and an unlocked multiplier, this might be the new processor to get if you yearn for 8 processor cores (and remember, that's 16 threads). This processor has a really low 65 Watt TDP thanks to its lower base frequency. The processor has already been shown on stage and has been compared to a Core i7 9700K (and was significantly faster) with roughly similar single threaded performance. So yes, until a non-X model of the 3700 is released, this proc imho is likely to bring a smile to the faces of many.

AMD is also releasing the Ryzen 5 3600 series with initially two products, both have six cores and twelve threads and sit in a 200~250 USD price bracket which is going to serve the mainstream segment excellently. Above, a breakdown of the processors announced. Both hexa-cores get SMT (Hyper-threading) and thus twelve threads. They are rated at a 95W TDP for the 3600X and just 65W for the 3600. The 3600 costs 199 dollars and the 3600X, 249 dollars.

Chiplet design

AMD is now effectively moving towards a chiplet design starting with Ryzen 3000, aka ZEN2. Multi-die chips, thus multiple chips in one package is what we're talking about when we refer to a chiplet design, it’s one of the many answers to be able to fight off Moore's Law, now and in the future. AMD was already using the technology to connect multiple processors in Threadripper and, for servers, Epyc. Actually, also Intel with Kaby Lake-G. Chiplets, these are multiples of chips put together on an interposer that form the actual chip. Chiplets for AMD Ryzen 3000, Zen 2 feature a I/O die along with 7nm CPU chiplets (each holding eight cores per die). To be able to accomplish that, AMD has been updating its Infinity Fabric that connects the different dies that hold the cores. Current Epyc, Ryzen and Threadripper CPUs are all connected via the Infinity Fabric.


With the Zen 2 architecture, AMD places one I/O die chip that sits in the middle, which is connected to two 8-core dies. These AMD CPU chiplets are connected with 2nd generation Infinity Fabric (the interlink wires that connect them all). Why chiplet designs? One of the bigger issues at hand when manufacturing large monolithic CPU/GPU dies is that yields decrease nearly exponentially, and costs go up due to non-working dies. Multiple smaller chips in one package have higher yields, less loss and thus can be more profitable. 


Zen 2 architecture is an advancement of Zen, and Zen had some bottlenecks that need to be dealt with. These are solved in this design and, at the same time, thanks to the smaller 7nm transistors, added extra functionality in important places. The image below shows the block diagram of the Zen 2 core. You will spot a new branch predictor, a larger micro-op cache, an additional address generation unit and a new floating point unit, which can handle 256-bits at the same time. 


You are going to notice some differences between the three cache levels. The L1 instruction cache has become smaller, the data cache is the same as last gen. The L2 cache is also the same, however the L3 cache was doubled up from last gen. AMD reduced the L1 instruction cache from 64 kB to 32 kB. The instruction cache contains the x86 instructions that are retrieved from the memory for processing. However, by giving this cache more inputs and outputs, 8-way associative instead of 4-way associative, it will make up for that design choice. Also, by optimizing algorithms for pre-fetching instructions and increasing the caches at other levels (like the L3 cache), the effect of the smaller instruction cache is limited. The L1 data cache was 32 kB in Zen and remains at 32 kB for Zen 2. Also unchanged is the L2 cache, which is still 512 kB per core. The L3 cache, however, is shared by the cores and that one has doubled up in size. Four cores are partitioned together in a group called a core complex (CCX). The earlier generation Zen processors had 8 MB of L3 cache, this has been doubled up to a whopping 16 MB of L3 cache. Why the double L3 cache? Well, AMD needed to address the latencies for accessing working memory to cope with the chiplet design, whereby the memory controller is physically located in a different chip, ergo a doubled L3 cache. Increasing any sort of cache is costly. It takes up a substantial portion of the available transistor budget, here is where 7nm helps out greatly.

Ryzen Gen 3 has also been fitted with an improved branch predictor that is now working according to a TAGE algorithm. Scientific studies are indicating that this model predictor offers the best results. Also, an important adjustment is to double the size of the micro-op cache to 4000 instructions. Substantial changes in the new design were also made to the floating point execution units, calculation units that basically do math processing like addition, subtraction, multiplication, division, square root, and bit-shifting. Zen supported 128-bit, Zen 2 makes a move towards 256-bit which brings us to support for AVX2 instructions, these can be processed in one single clock-cycle now. Zen2 does not yet support AVX512. 

Load/store units have been optimized by doubling bandwidth from 16 bytes per clock cycle to 32 bytes per clock cycle. L/S units transport data to and from the caches and, via that route, to and from the memory.

A perf gain - Instructions per cycle (IPC)

All optimizations from Infinity Fabric, to the predictor to caches and op-caches combined, make Ryzen 3000 a faster architecture. Roughly 15% per clock cycle, and in processor land that is massive. 7nm also allows high clock frequencies. The first generation Ryzen (14nm) could achieve a maximum clock frequency of 4.0~4.1 GHz. This third generation Ryzen increases that by another notch to 4.4~4.6 GHz. And few higher-end processors even go beyond that value, the 16-core Ryzen 9 3950X, for example, will see a Turbo frequency of 4.7 GHz.


CPU hardening

What I also wanted to share for now is that AMD has further secured their procs in hardware, there is CPU hardening for Spectre v4 exploits built into the processor, which is awesome news. The AMD processors have never been susceptible to other security issues such as Meltdown, Foreshadow, and MDS.


Share this content
Twitter Facebook Reddit WhatsApp Email Print