When AMD announced the Ryzen 9 3950X in June 2019, I wasn’t immediately sure what to think. Taking the original Ryzen platform up to 16 cores from the eight that it launched with offered a very significant upgrade path to first-generation Ryzen buyers, but it also raised questions about whether two memory channels would be enough to keep the CPU fed.

AMD delayed the Ryzen 9 3950X by a few weeks, possibly to improve inventory levels, but the company’s 16-core CPU is finally here. The Ryzen 9 3950X is the “full fat” edition of the desktop Ryzen family, with two physical chiplets and an I/O die, with all eight cores enabled on both die.

Here’s how AMD’s Ryzen stack looks these days, with per-core pricing.

At $750 for 16-cores, the 3950X is a fair step up from the $500 price point, and the increase in core count (1.33x) doesn’t quite match the increase in price (1.5x). This isn’t uncommon at the high end of the market, however, and the price to leap from Intel’s mainstream desktop segment to its HEDT platform has always been far higher than this.

The Ryzen 9 3950X is a rare CPU. First, AMD and Intel CPUs with the highest core counts don’t typically field the highest single-threaded clocks at the same time. Second, while there have been points in the past where it was possible to boost CPU core counts over and above what was available when a hardware platform launched, it doesn’t happen all that often. Third, the CPU sits at a unique point in AMD and Intel’s respective product stacks.

In AMD’s case, the 16-core 3950X is the effective replacement for last year’s Ryzen Threadripper 2950X. The old Socket TR4 platform won’t be upgraded with a third-generation chip and the new TRX40 third-generation Threadripper platform will start at 24 cores and stretch up to 32.

The Ryzen 9 3950X is also AMD’s attempt to retake a platform advantage it held over Intel in Ryzen’s early days. Until Intel launched the 8700K, AMD had an eight-core CPU sharing space in the mainstream desktop market with an Intel platform that topped out at four cores and eight threads. Coffee Lake reset things a bit closer to parity later that same year, but AMD undoubtedly liked being able to queue up 2x the CPU cores in an apples-to-apples comparison. With the Ryzen 9 3950X, it can do that again.

Finally, the Ryzen 9 3950X is unique in the sense that Intel isn’t lining up another CPU exactly against it in terms of core count. At ~$500, you’ve got chips like the Core i9-9900K. When Cascade Lake-X launches, the 3950X will be bracketed by the Core i9-10920X (12-core, 3.5GHz / 4.6GHz, $700) and the Core i9-10940X (14-core, 3.3GHz – 4.6GHz, $800). Intel isn’t building a 16-core Cascade Lake X, however — the core count and price jump from 14 to 18 and $800 to $1K, respectively.

Watching for Memory Bandwidth Pressure

The big question going into the 3950X’s debut is whether two DDR4 channels can deliver enough memory bandwidth to feed 16 cores. Dual-channel DDR4-3600 provides 57.6GB/s of memory bandwidth, but that only works out to about 3.6GB/s of bandwidth per CPU core. That’s about 10 percent more RAM bandwidth than a single channel of DDR-400 provided back in the day — and that might sound like a recipe for disaster in a CPU like this.

But a lot has changed since the days when single-channel DDR configurations roamed the Earth. Caches are much larger, prefetching algorithms have improved, and the widespread adoption of SMT offers opportunities to hide memory access latencies. It’s not clear if the Ryzen 9 3950X is particularly memory-bandwidth limited, but we’ve spun the Threadripper 2950X up to test the theory. While we can’t do an exact apples-to-apples test without a third-generation Threadripper to evaluate, any benchmark where the 2950X takes an unusual lead could be a sign it’s leveraging additional memory bandwidth.

Test Setup

The AMD Ryzen 9 3950X was tested in the same OS image and Windows 10 SSD configuration that we used for our 7/7 initial review. Chipset drivers were updated to the latest for download on AMD’s site (1.9.27.1033). Windows 10 1903 with the latest updates and patches was used. Our MSI X570 Godlike motherboard was updated to the latest beta UEFI (7C34v17, dated 11-07-2019). This UEFI is based on AMD AGESA 1.0.0.4. Nvidia GeForce driver 430.86 was used to maintain identical configurations with our previous round of testing.

Each of our testbeds had 16GB of RAM except for our Threadripper 2950X and Intel Core i9-9980XE platforms. These two systems used 32GB of RAM to load each DIMM channel. The third-generation Ryzen CPUs were outfitted with DDR4-3600, while the Intel platforms used DDR4-3200. Intel systems generally care less about RAM clock than AMD systems in any case.

The Threadripper 2950X was tested in the MSI X399 Creation motherboard and tested with Precision Boost Overdrive (PBO) enabled. This represents something of a “best foot forward” scenario for Threadripper, but we wanted to give the CPU its best opportunity to shine in comparison with the Ryzen 9 3950X. Using PBO on a Threadripper voids its warranty.

The Core i9-9980XE’s inclusion here warrants some discussion. The Core i9-9980XE is vastly outside the Ryzen 9 3950X’s price range — but this was also true for the Threadripper 2950X versus 9980XE comparison. At the top of the market, we have to compare the parts that exist. Furthermore, the Cascade Lake X family drops in the not-too-distant future, bringing significant price cuts. We don’t know how much faster the 10980XE is compared with the 9980XE, but we can treat this chip as a low-but-rough-approximate of what the 10980XE’s performance should look like.

The point of including the Threadripper 2950X and the Core i9-9980XE is to see how the newer part changes the shape of what has come before, and maybe to get a sneak preview of what the Cascade Lake versus Ryzen performance comparison is likely to look like.

Finally, the graphs here are going to be a bit… lorge.

The sheer number of data points we’re comparing makes this unavoidable. Nine CPUs — four Intel, five AMD — is a lot of data to juggle. The Ryzen 7 2700X and Core i7-8086K are retained to give some performance data on last-gen chips. The 9700K gets included because it’s kind of an oddity — slower than the 8086K in some things, but Intel’s overall fastest gaming chip if what you care about is pure frame rate. The 9900K is Intel’s top-end mainstream desktop chip. The Threadripper 2950X is included to check for any signs of memory bandwidth shortfalls now that AMD is putting 16 cores on just two memory buses, and for the most direct 16-core to 16-core comparison. Threadripper’s vastly higher TDP (180W versus 105W) also give it potentially more headroom to work with.

Before we hit the slideshow, here’s our Blender 1.0Beta2 benchmark results.

The Ryzen 9 3900X and the Threadripper 2950X are near-evenly matched, trading wins with each other across the test. The Ryzen 9 3950X consistently renders in 76-77 percent the time of the 3900X. The Core i9-9980XE is overmatched in most tests, though it does win the Barbershop_Interior test by a full minute.

Our other test results are included in the slideshow below. I’ve had to remove all 7zip results due to cross-contamination between 32-bit and 64-bit results, and will be restating these results for previous reviews as well. Handbrake is now included.

Handbrake and our 3D rendering performance results show the 3950X is truly best-in-class. There’s no evidence of bandwidth-related limits as far as 3D rendering, compiling, or Handbrake. Overall, the Threadripper 2950X competes most effectively with the Ryzen 9 3900X. That’s not the worst position for that CPU to be in, but it does show how much improvement AMD has delivered in a single generation. As for the Core i9-9980XE, it still logs some wins, and we see some narrow evidence of Threadripper’s bandwidth superiority in DigiCortex, but the 3950X notches up some single-threaded wins for itself that AMD hasn’t held for a very long time. That’s not everything — but it’s not nothing, either.

Gaming performance is up next. This is often the place where I note that GPU performance varies only a little at the top-end of the market and that the differences between these CPUs are narrow. That’s not quite the case today, however — and while 1080p isn’t necessarily a likely gaming resolution for these CPUs, it’s still worth taking a look through these results to see where these CPUs land.

Gaming performance shows a few surprising wins for the Ryzen Threadripper 2950X, but the Ryzen 9 3950X hits higher frame rates overall and offers more regular performance besides. While it still doesn’t quite catch Intel in lower-resolution tests, the gap between the two CPU families is the smallest it’s ever been thanks to the 3950X. The fact that AMD is delivering performance gains like this in a high-core part is particularly impressive. It doesn’t make the high-core CPU a good choice for people who principally game — but it does mean that you have to give up much less performance in gaming with the 3950X than with previous solutions — including, in a few places, the 9980XE.

Conclusion

For $750, the Ryzen 9 3950X is an unbeatable CPU. While it’s true that Intel’s 18-core Core i9-9980XE retains a reasonable number of test wins, compare the 2950X with the 3950X to see just how much AMD has improved performance year-on-year. Twelve months ago, the 2950X wasn’t taking any tests off the Core i9-9980XE — the combination of two additional CPU cores and Intel’s higher overall IPC was a barrier second-generation Threadripper wasn’t capable of scaling very often. And up until now, the single-threaded Cinebench results have been Intel’s sole turf. Cinebench is not the be-all-end-all of performance measurement, but these are still tests that Intel has been reliably winning for at least a decade.

The Ryzen 9 3950X is a further uplift over the 3900X and the 3700X in both single-threaded and (obviously) multi-threaded performance. There’s no evidence of any bandwidth constraints in ordinary desktop applications or games — the 3950X is often the fastest Ryzen CPU on the market where gaming is concerned. This should not be read to indicate that I’m recommending a 16-core CPU for gaming — that’s ridiculous overkill, and I very much am not. But the 3950X takes a number of significant tests in this area as well, and in a way that’s unusual for high-core-count chips.

The fact is, Intel doesn’t have a particularly great competitive answer to the Ryzen 9 3950X in this price bracket, and the launch of Cascade Lake in a few weeks isn’t necessarily going to help them in every space. We can assume that Cascade Lake X will be a touch faster than the current Core i9-9980XE, and obviously that’ll improve Intel’s position at the $1000 price point. What it won’t do, however, is provide an equivalent boost for Intel’s mainstream desktop platform, which still tops out at eight CPU cores.

Now, Intel deserves (and will get) credit for slashing the price on its Cascade Lake CPUs, but $1,000 is still more than $750 and an HEDT motherboard is still a bit more expensive than an X570. Figure a $50 motherboard price difference and $250 for the CPU, and the Core i9-10980XE will still carry a $300 premium. Buyers who are willing to step up to HEDT may still be willing to choose Intel over desktop Ryzen, but the Ryzen 9 3950X offers horsepower the 9900K can’t even touch in the mainstream socket space.

Do you need a Ryzen 9 3950X? Probably not. If you’re a gamer, CPUs like the Core i7-9700K or the Ryzen 7 3700X are going to be far more cost-effective and practical. But the Ryzen 9 3950X represents the pinnacle of AMD’s single-threaded and multi-threaded performance. It offers both of those things in the same CPU rather than asking users to choose between one or the other. It demonstrates sustained, multi-year double-digit performance improvements, even considering the constraints of bringing a 16-core part into a dual-channel memory configuration — constraints which do not seem to bind third-generation Ryzen as much as some, including myself, were concerned they might. Further research is warranted, and there will be workloads where memory bandwidth is necessary, but the trends are positive. Most Ryzen upgraders will be better served by an eight-core chip, but AMD users who need the firepower 16 cores can offer will not find them lacking.

As impressive as the Ryzen 9 3950X is, it’s just the opening salvo in AMD’s November 2019 72-Core Launch Salute. Threadripper 3 is coming.

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