AMD Ryzen 9 3900XT, Ryzen 7 3800XT and Ryzen 5 3600XT Review: Small Gains, Big Price Tag

AMD's new Ryzen XT lineup comes as a refresh that's designed to tackle Intel's new Comet Lake processors. The XT family brings three new flagships to bear: The Ryzen 9 3900XT, the Ryzen 7 3800XT, and the Ryzen 5 3600XT that will all vie for a spot on our list of Best CPUs. Surprisingly, on the surface, the XT lineup looks a lot like what we've seen in the past from Intel: An iterative lineup of chips with small differentiation from their predecessors in terms of features and clock speeds, not to mention the same number of cores, same process node/density (albeit with some refinements), and the same microarchitecture as their predecessors.

AMD even eliminated bundled coolers from two of its three new models, which runs counter to its standard value proposition of throwing in all the goods with each chip. Overall, the Ryzen XT series doesn't appear to have the explosive gains like we're used to with AMD's gen-on-gen improvements, but there's a lot more nuance to the XT story than what we see on the spec sheet. 

A quick glance at the spec sheet shows most of the key specifications remain unchanged, with the most substantial change being that the 12-core 3900XT comes with a 100 MHz higher boost, the 8-core Ryzen 7 3800X gains 200 MHz, and the 6-core Ryzen 5 3600XT gains 100 MHz.

Due to refinements to the 7nm node, AMD says it improved boost frequencies by 2-4%, but it also improved boost residency, or how long the processor remains at its boost frequency, by up to 80%. Combined with the incrementally higher clock speeds, AMD says the improved boost residency improves lightly-threaded performance by 4-5%.

As we'll cover below, the minor increases to boost frequencies that we see on the spec sheet don't take into account that the processors now have more room to boost higher in mid-threaded workloads (those that don't fully saturate all of the cores). That capability delivers up to 10% more performance in some workloads, but we found those are pretty rare. AMD wrung out this extra performance while leaving key power limitations unchanged, meaning you get more performance within the same maximum power envelope. 

We also see some gains in gaming performance, albeit not of the explosive sort. AMD says you can expect about a 2% improvement with the 3900XT and a 4-5% improvement with the 3800XT, depending on the title. We didn't see as much uplift, though. As expected, games that respond to lightly-threaded performance benefit the most, so gains can be scattered. 

AMD advises that these processors aren't meant to be a direct upgrade path from existing Ryzen 3000 processors. Instead, the existing chips will still be available at retail. The new XT-branded chips will serve as another choice for customers if they're upgrading to a Ryzen processor for the first time, or refreshing an older rig. 

You'll need to bring your own 280mm (or greater) AIO liquid cooler for Ryzen XT 9 and 7 chips, though, which adds to the pricing significantly. We did record slightly improved performance from the auto-overclocking PBO feature over prior-gen models, but AMD also says you shouldn't expect higher manual overclocking frequencies from the new chips. 

Overall the Ryzen XT processors offer incremental performance increases in gaming that aren't worth a direct upgrade, and most gamers are better suited with either AMD's existing models or Intel's competing chips – The Ryzen XT series doesn't change the gaming landscape much. If gaming is your primary focus, you'll be better served with less expensive Ryzen alternatives, like the Ryzen 7 3700X or the Ryzen 5 3600X. The Core i5-10600K is another solid choice that leads our list of Best CPUs.

Due to the performance characteristics of the XT models, they're a decent step up over the standard models if you frequently use productivity applications that aren't exclusively heavily-threaded. The Ryzen 9 3900XT and Ryzen 7 3800XT, in particular, deliver great gains in a few productivity apps, like Photoshop and Adobe Premier, so paying a bit extra for the chip only makes sense if you already plan on using an aftermarket cooler and use those types of apps almost exclusively. 

AMD Ryzen 9 3900XT, Ryzen 7 3800XT, and Ryzen 5 3600XT

The Ryzen XT processors come with a familiar piece of branding - the 'XT' moniker from AMD's Radeon Technology Group (RTG). AMD brought the XT branding to its CPUs to denote they are refresh chips with higher performance potential than their X-series counterparts. That works well for the company from a 'cross-branding' standpoint, and we could see more XT-branded chips in the future, too. AMD says it didn't add a 16-core 32-thread Ryzen 9 3950X "XT" model to the stack because it already has the performance crown on the mainstream desktop. 

Like the other Ryzen 3000 series chips, the XT models are drop-in compatible with any existing motherboard with a Ryzen 3000-ready BIOS and all 500-series motherboards. As before, the chips support up to DDR4-3200, but official support varies based on the type of DIMM and number of populated channels. 

The $499 Ryzen 9 3900XT, $399 Ryzen 7 3800XT, and $249 Ryzen 5 3600XT land with the same suggested pricing as the existing Matisse models, meaning the XT models aren't a price-reducing update. Both lineups will coexist in the market.

AMD's SEP (Suggested Etailer Pricing) has little connection with the reality you see at retail, so you can already find the existing Ryzen 3000 series processors far below the SEP. We could see the already-solid pricing on X-series Ryzen chips get even better in the wake of the XT models, too.

Given the volatile pricing we see with existing AMD chips, the new XT models will probably retail below MSRP in due time, too, muddying the competitive landscape. For now, the Ryzen XT 9, 7, and 5 processors square up with Intel's flagship Core i9, i7, and i5 chips, particularly the -KF models that, like the XT chips, come without integrated graphics.  

AMD didn't improve the base frequencies because the company says the processors rarely operate in these low frequency ranges, even during heavily-threaded workloads that fully stress the processor and trip power governors. That's a fair argument, and unlike Intel, AMD doesn't spec Ryzen 3000's TDP metrics solely at the base frequency, so the base frequency specification isn't as important.

The XT processors adhere to the same 105W and 95W TDP ratings as their predecessors, but more importantly, feature the same PPT (Package Power Tracking) variable that defines the upper limit of power delivered to the socket. That means the Ryzen 9 and 7 models can peg the needle at 142W of maximum power draw, while the Ryzen 5 3600XT tops out at 88W. 

AMD's boost frequency improvements also apply when the processor is under load, so multi-core boosts are also improved. However, that comes with a caveat: The core-heavy 3900XT can hit its PPT limit before all of its cores are stressed, which restricts possible performance gains. AMD also enforces its other existing power limits, like the TDC (sustained current) and EDT (spontaneous current) variables, at the same levels as previous-gen models. As a result, most of the 3900XT's enhanced boosting capability occurs during light- to mid-threaded workloads where those limits aren't a factor. 

Meanwhile, the Ryzen 7 3800XT and Ryzen 5 3600XT have fewer cores, and thus don't encounter the limits as easily. That means we should see higher performance gains with the Ryzen XT 7 and 5 models in threaded workloads.

AMD claims the 3900XT now holds the single-threaded performance crown, wresting it from Intel's aging Skylake architecture, but it's noteworthy that distinction appears to be based specifically on Cinebench benchmarks. Our testing found that Intel still holds the overall single-threaded crown when we look at a broader spate of workloads and data types. However, as you'll see on the following page, AMD has significantly increased both its boost speed and boost duration with the XT models.

What? No Cooler with Ryzen XT Processors?

AMD's unrestrained feature sets have earned it plenty of cachet with enthusiasts and casual users alike. Things like multi-threading and overclockability come standard with nearly every model, and the company used to provide bundled coolers with all SKUs. However, the Ryzen 9 3900XT and Ryzen 7 3800XT models both come without a bundled cooler: You'll need to provide your own 280mm (or greater) AIO liquid cooler (or equivalent air cooler), which adds to platform costs. Meanwhile, the Ryzen 5 3600XT comes with a bundled Wraith Spire cooler like its X-series counterpart, the 3600X. 

This isn't entirely without precedent – AMD also doesn't provide a cooler with the 16-core 32-thread Ryzen 9 3950X, and for many of the same reasons. AMD defines important characteristics of chip performance based upon the bundled coolers' ability to dissipate thermal load, so the company uses the bundled cooler to define the frequency, power, and performance targets. (Intel also takes the same approach with its chips that come with bundled coolers.) 

Due to AMD's adaptive Precision Boost 2 algorithms, much of the Ryzen 3000 series processors' performance relies upon the capabilities of your motherboard and cooling, with the latter having a big impact on peak frequencies and boost duration/residency. By requiring a larger cooler, AMD can spec the processor and define performance targets based on the improved thermal dissipation capability, thus ensuring that you realize longer and higher boost frequencies. Given that the cooler plays a big role in the performance uplift we see with the new chips, it's hard to say how much of the performance gains stem from cooling or the enhancements to the 7nm node, but it's probably a mix of the two. However, given like-for-like AIO cooling, the XT models have proved to be faster than the previous-gen models in our testing.  

AMD also says that 60% of enthusiasts don't use the bundled cooler, but the company didn't cite a source for that prediction. As such, the company feels that these performance-oriented models will most likely be paired with an aftermarket cooler. In contrast, the Ryzen 5 3600XT comes with a bundled Wraith Spire cooler because AMD feels that enthusiasts shopping in this price range are more likely to use the bundled cooler. 

AMD Ryzen XT Architecture and 7nm Process Node

The Ryzen XT models come with the same Zen 2 microarchitecture as their predecessors, so transistor density, CCD alignments, and other particulars are the same. AMD says it uses a 'better recipe' for the same 7nm node, so it "contain(s) materially better transistors than those found in prior third-gen AMD processors."

AMD cites reduced voltage and leakage along with improved operating frequencies as a result of node enhancements, but the company will not share details of the specific optimizations. We do know the XT models use the same node as the original 3000-series processors, though. According to monitoring utilities, the XT models even come with the same B0 stepping die as the preceding X-series models.  

TSMC has three 7nm options. N7 is the DUV node largely thought to be used in Ryzen 3000 series processors. N7P (Performance Enhanced) is a second-gen version of N7 that comes with up to 7% more performance at iso-power (or 10% lower power at iso-speed) but remains on DUV manufacturing. Finally, N7+ comes with EUV lithography and is ~1.2X denser and isn't IP-compatible with the preceding two nodes, meaning it requires a significant amount of design work and validation to port over an architecture.

AMD hasn't specifically said which flavor of the 7nm process it uses for the 3000-series, but given that N7P only debuted in 2019, it's logical to expect the company uses N7.

AMD's first Zen 3 processors will land later this year with the 7nm process, which AMD previously marked as 7nm+ on its roadmap. AMD later altered the Zen 3 listing on its roadmap to "7nm" to align with TSMC's changing nomenclature. That means we could see either N7P or N7+ come with the Zen 3 processors, though the former seems more likely.

Regardless, the improvements with the XT series aren't as impressive as we saw from the second-gen Ryzen processors, which moved from the 14nm GPP process with Ryzen 1000 to the 12nm LP process. That transition wasn't an optical shrink, so it also didn't impact die area or transistor density, but it also resulted in improved transistor performance.

The move to 12nm LP netted 300 MHz higher clock rates or a 50 mV core voltage reduction at any given frequency compared to 14nm, and AMD also used higher-performance libraries in critical pathways, which resulted in lower cache and memory latencies. The Ryzen 2000 series also brought improved Precision Boost 2 and XFR2 algorithms, which helped push performance further. 

AMD isn't as forthcoming to the changes with the Ryzen XT series, so we aren't sure if the company has made significant changes to the libraries, or the nature of its other tweaks. 

Caching Up With StorMi V2 and Ryzen Master

AMD updated its Ryzen Master software, which you can use to monitor and adjust critical parameters of Ryzen processors (including overclocking). The new version has a new basic view for novices. This reduces the complexity of the full-featured program by only displaying the parameters in the screenshot below. 

Image 1 of 2

StoreMI, which comes free with AMD processors, is a storage acceleration technology that combines an SSD and HDD into one volume, with the most frequently-accessed files being stored on the faster SSD. This approach blends the speed of flash with the capacity and pricing of an HDD.

The original StoreMI operated in a tiering implementation that expanded the capacity of the hard drive, so the technique moved data from the HDD to the SSD for acceleration. As a result, the system only maintained one copy of the data. That exposes users to potential data loss in the event of a power failure or BSOD, but it gives you more usable capacity than caching. For instance, if you combine a 1TB SSD and a 1TB HDD, you get 2TB of addressable storage. 

AMD's new StoreMI version 2.0 uses a caching implementation, so combining the 1TB SSD and 1TB will only yield 1TB of addressable storage. With caching, the capacity of the SSD basically vanishes when you use it to accelerate an HDD. That's because caching stores a copy of the data on both the SSD and the HDD.

The new approach also only caches read-only data on the SSD, while the previous version also absorbed incoming write traffic on the SSD to speed random write workloads. That, too, left users potentially exposed to data loss, and often for slim gains in real-world workloads. In effect, read caching gives you the lion's share of accelerated performance that you would get with a tiering implementation, but with far less risk. 

Caching is a safer path to storage acceleration, but it comes at the cost of usable capacity. Now AMD lets you mix and match SSDs and HDDs of any capacity, though, while the previous version of StorMI had limits of a 256GB SSD and 2TB HDD. 

AMD says the new approach speeds up boot times by 31% and decreases game load times by 13% compared to an HDD, but didn't provide performance comparisons to the previous StoreMI version. StoreMI also has a simplified user interface, and although NVMe storage is cheap enough that most enthusiasts will opt for a new SSD-only boot volume, StorMI is essentially free for the more value-conscious among us.

StorMI V2 debuts on the X570 platform first. Updates for existing Ryzen platforms, like X470, B450, B550, TRX40, and X300, will release on a rolling schedule throughout Q3 2020.