AMD Ryzen 9 3950X Review: 16 Cores Muscles Into the Mainstream

AMD's Ryzen 9 3950X lands today, bringing the ultimate threaded performance to the mainstream desktop with an industry-leading and unprecedented 16 cores and 32 threads, paired with the bandwidth-doubling PCIe 4.0 interface for $749. The CPU upsets Intel's positioning in mainstream desktops and disrupts it's vaunted high-end desktop (HEDT) lineup in the process. 

Aside from the deep dive on the CPU that we're tackling here, we've also tested and reviewed they Ryzen 9 3950X in Alienware's redesigned Aurora R10 gaming desktop. That system trounced competing high-end gaming rigs in many productivity tests. But Dell did a questionable job on the cooling front, including a single intake fan and a small radiator with the AIO liquid cooler.

AMD's Ryzen family has completely redefined our expectations for desktop processors, and Intel has struggled to respond. The company has slowly dialed up the frequency of its aging 14nm process and added more cores, but those tweaks can't offset the reality that AMD has moved onto a denser and more efficient 7nm process that enables higher core counts. Of course, process technology doesn't solve all the challenges of fielding a competitive chip, but that advantage is hard to beat when paired with a solid microarchitecture like AMD's Zen 2. 

A few months ago, AMD moved the industry again with the 12-core Ryzen 9 3900X but left us with the promise of something even more powerful: The Ryzen 9 3950X that completely upsets the paradigm with 16 cores and 32 threads, encroaching on both Intel's Skylake-X Refresh HEDT lineup and AMD's own Threadripper platform. To say this chip blurs the lines between the mainstream desktop and HEDT is an understatement: In reality, it brings HEDT-class performance to the friendlier pricing of mainstream motherboards, placing it in a class of its own. 

Both companies will update their HEDT lineups later this month, with AMD plowing ahead to 32-core Threadripper 3000 chips (possibly 64 cores in the future), while Intel releases yet another iteration of its Skylake-derived 14nm silicon with its Cascade Lake-X lineup. But Intel's chips will still top out at 18 cores, only two more than AMD's 3950X, and require a pricey X299 platform that comes equipped with the PCIe 3.0 interface. Meanwhile, AMD leads the industry with PCIe 4.0. 

From early indications, Intel's mainstream Comet Lake processors will arrive next year with a maximum of 10 cores, leaving AMD with the uncontested core count lead for quite some time.  

Perhaps Intel tipped its hat on its perception of the 3950X and Threadripper 3000 chips when it slashed its Cascade Lake-X pricing in half before either of AMD's competing chips even came to market.

But while we await the Threadripper 3000 goodness, we have the beefiest chip to ever drop into a mainstream motherboard: The Ryzen 9 3950X that features nearly as many cores as Intel's HEDT flagship. Let's see how it stacks up.  

Ryzen 9 3950X Specifications and Pricing

Ryzen's 7nm process offers density advantages that manifest as higher performance, better power efficiency, more cores, and more cache packed into a smaller area than the first-gen Ryzen models. Like the Ryzen 9 3900X, the 3950X comes packing AMD's Zen 2 microarchitecture spread across two small 7nm eight-core compute chiplets tied together with the Infinity Fabric interconnect via a larger 12nm I/O die (IOD). 

Each small compute chiplet, referred to as a CCD (Core Chiplet Die), comes with eight physical cores. All told, the chip sports ~9.89 billion transistors, and they are all active: Unlike the 12-core 3900X, all 16 of the 3950X's hyper-threaded cores are enabled, forging a 16-core 32-thread beast that fits inside the confines of a chip that drops into the AM4 socket on mainstream motherboards. You can learn more about the design here.

The Ryzen 9 3950X comes with AMD's highest-binned silicon to enable a 4.7 GHz boost clock, but like other Ryzen 3000 processors, it comes with a mix of faster and slower cores. 

AMD weathered plenty of criticism in the immediate aftermath of its Ryzen 3000 launch because not all of its chips could hit the rated boost clocks, but a series of BIOS fixes have mostly addressed those shortcomings. The Ryzen 9 3900X seems to suffer the most from the issues, leaving some users unable to hit its 4.6 GHz boost clock. The 3950X features a 100 MHz higher boost clock than the 3900X, so naturally there has been some speculation that it, too, will not satisfy its boost specfication. We put that to the test, which we'll cover on the next page. Spoiler alert: We had no issues reaching the rated 4.7 GHz (and slightly beyond), though it isn't a sustained boost like we see with Intel's chips. 

Cooling comes into play, though. The 3950X comes with an AMD-defined 105W TDP just like the 3900X, but the four extra active cores require a more robust cooling solution. As a result, the 3950X doesn't come with a bundled cooler, a first for AMD's mainstream Ryzen chips in this generation. AMD recommends a beefy 280mm AIO cooler as the entry-level solution, but as you'll see, better cooling yields better performance. 

As expected with a core-heavy chip, AMD pared back the base clock to 3.5 GHz, but the chip retains the same 64MB of L3 cache as the 3900X along with access to 24 lanes of the PCIe 4.0 interface. The PCIe 4.0 interface provides twice the potential throughput from speedy SSDs and networking additives than Intel's chips, which remain mired on PCIe 3.0. The faster interface doesn't improve gaming performance, so it isn't as important for mainstream chips as it is with the Ryzen 9 3950X. Plenty of semi-professionals and creators will adopt this platform due to its HEDT-like slant, and those users will appreciate the higher throughput for productivity applications. 

Like AMD's other mainstream processors, the 3950X supports dual-channel DDR4-3200 memory, but there are caveats based upon DIMM type and population. 

The 3950X's $749 price point places it in a tier above Intel's current mainstream halo part, the $488 Core i9-9900K. Intel also has its Special Edition -9900KS on offer, but that chip is only available for a limited time so it doesn't fit into the long-term view. 

Instead, the Ryzen 9 3950X lines up against Intel's HEDT Core i9 models. However, the current-gen Skylake-X refresh products, like the Core i9-9920X and -9960X, aren't competitive at current pricing (though it does appear we will see price cuts on those models soon). 

That means we have to turn to Intel's Cascade Lake-X processors, which land later this month, for relevant comparisons. Oddly, Intel has left open a core-count gap in its HEDT lineup, so it doesn't have a 16C/32T chip to compete directly with the 3950X. At least not yet. 

Ryzen 9 3950X Motherboards

The 3950X drops into the standard AM4 socket on X570, X470, and B450 motherboards, though you should select one with robust power delivery accommodations to feed the 3950X. AMD has only validated the Ryzen 9 3950X with its new 1.0.0.4B AGESA code, which motherboard vendors are rolling out for existing motherboards (via a firmware update) over the course of this month. AMD strongly recommends that all Ryzen users to migrate to the new motherboard firmwares.

The new firmwares include many of the fixes we've seen for AMD's boost clock algorithms, along with even more refinements that include faster boot times. This new BIOS also unifies all the Ryzen models under the same codebase, so there won't be any more split support for some older models. 

Contrary to rampant speculation and some claims from motherboard vendors, the 1.0.0.4B firmware doesn't appear to impart any magical performance gains on the existing line of Ryzen processors. We retested the Ryzen 9 3900X and 3700X with the new firmware at both stock and auto-overclocked settings, and all of the results you'll see today reflect those results. We did find some performance improvements with AMD's auto-overclocking Precision Boost Overdrive (PBO), but most of the benchmarks fell within range of previous BIOS revisions. We did notice the faster boot times, which are appreciated, but stock performance is roughly equivalent. 

MORE: Best CPUs
MORE: Intel & AMD Processor Hierarchy
MORE: All CPUs Content