AMD's Ryzen 7 5800X3D is among the most intriguing new desktop processors from the company since the introduction of its first Ryzen chip in 2017. In many ways, the Ryzen 7 5800X3D is no different from the Ryzen 7 5800X launched in November 2020, except the 5800X3D has a gargantuan amount of cache attached. This cache is based on AMD's 3D V-Cache technology, and it gives the chip a total of 96MB of Level 3 cache. The processor's MSRP is unchanged at $449.99. (Real-world pricing is another matter, which we'll get into near the end of this review.) It seems AMD hoped the new CPU's extra cache would boost gaming performance and create a processor that would dominate the gaming-CPU market until the Ryzen 7000 series was ready this fall. Alas, unless you're a diehard esports gamer looking to play games at over 300 frames per second (fps) at 1080p resolution, a lesser, cheaper Ryzen 7 should do you just fine.
The Value of Cache
To understand the design decisions behind the Ryzen 7 5800X3D, you must understand cache and how it works inside of a processor. Cache is an often underappreciated, yet vitally important, piece of any modern-day CPU. The number of processing cores and their clock speed are typically what people pay the most attention to. These are unquestionably important, but without the right amount of cache, performance can slow to a crawl.
In many ways, CPU cache is similar to a system's RAM, but much smaller and much faster. Most processors today have three types of cache, labeled Level 1, Level 2, and Level 3 (usually abbreviated to L1, L2, and L3). All work to fulfill the same basic purpose: keeping the CPU cores filled with the information they need when they need it.
Perhaps the easiest way to explain the relationship between system memory and the various types of cache is to picture the inner workings of your PC as a factory, with a CPU core as the primary machine constructing the goods. In this scenario, your computer's RAM would be a large local warehouse attached to the factory that holds the raw materials needed for production. Think of the Level 3 cache as a forklift used to move materials from the warehouse to the factory floor; L2 cache as a handcart used to move the materials to the constructing machine itself; and L1 cache as where the material is actually loaded into the machine.
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When everything goes smoothly, data flows from the system RAM to each level of cache in turn, ultimately making its way to the CPU processing cores. If the CPU doesn't find the data it needs to perform a task in the Level 1 cache, work grinds to a halt as it checks the L2 cache, then the Level 3 cache, then the slower main memory, and then finally the much slower local storage (a solid-state drive or hard drive). When the processor has to go looking for data, however, it's not getting any work done and it's wasting a lot of time. Removing that bottleneck has been a major area of computing research and development for decades, which is why all of these types of temporary and permanent data storage exist in the first place.
Knowing this, you might conclude it's always better to have more cache. Not necessarily: The CPU only needs so much data at any given instant, and there's no point (or positive return in performance) in providing it with more than it can handle.
Indeed, excess cache can actually be detrimental. Like all electrical components, cache requires power to operate and generates heat while working. It also costs money to manufacture, so adding unnecessary cache will only raise the cost of a processor while making it run hotter and siphoning more power from the CPU's supply.
Design: Stapling 64MB of Cache to the 5800X
Though the Ryzen 7 5800X3D utilizes the same "Zen 3" architecture as other Ryzen 5000 series processors, its design is unique. The most obvious change is that the 5800X3D is the first AMD chip to feature the company's 3D V-Cache technology, with a separate chip that contains 64MB of L3 cache attached onto the CPU core. Making this alteration required some fairly substantial changes.
Processors are designed to fit within a very specific area. AMD couldn't increase the height of the chip, as all AM4 CPU coolers expect the processor to be a specific height; a taller Z-axis would cause the coolers to place greater pressure on the CPU and could damage it. This made simply stacking the 3D V-Cache atop the Ryzen 7 5800X die impossible. But AMD was able to resolve this issue by thinning out the CPU die.
With the Z-axis off limits, AMD extended or flattened the design with a larger die area along the X- and Y-axes, creating a chip with 4.15 billion transistors that's 80.7mm square in total area. This reduced the height sufficiently that putting the 41mm-square 3D V-Cache on top of the chip yielded a Z-height matching a standard Ryzen 7 5800X. The 3D V-Cache itself contains 4.7 billion transistors; the space around it is filled with structural silicon dies that don't contain any transistors but help to add structural support to the two chips and dissipate heat from the CPU cores underneath.
The 3D V-Cache is molecularly bonded directly to the CPU die beneath, and the two chips are packaged together using a technique AMD calls "hybrid bonding." This reportedly supports far greater density than other bonding techniques—more than 15 times greater than micro bump bonding, while consuming one-third less energy. Pathways called Through Silicon Vias (TSVs) are used to interface the two chips together electrically and enable bandwidth between them of up to 2TB per second.
Apart from these rather significant alterations, the processor die itself is essentially the same. The die contains eight "Zen 3" processor cores that support simultaneous multithreading (SMT) technology to handle two threads simultaneously (i.e., 16 at a time). These cores have a base clock of 3.4GHz and can hit max boost speeds as high as 4.5GHz. The chip as a whole has a thermal design power (TDP) rating of 105 watts, and both chips are crafted on TSMC's 7-nanometer FinFET process.
The processor die already contained 32MB of Level 3 cache, which (combined with the 64MB 3D V-Cache) adds up to the advertised 96MB of L3 cache—as AMD calls it, though I'm tempted to think of it as Level 4 cache. It's functionally similar to L3, but is clearly a separate and distinct pool of cache. The 3D V-Cache is ever so slightly slower than the L3 baked into the CPU itself, with an average reported increase in latency of 3 nanoseconds, but that's still far quicker than the estimated penalty of 50ns to 90ns that would be incurred if the CPU had to wait for data to be fetched from system RAM.
Test Setup and Benchmarking
We tested the AMD Ryzen 7 5800X3D on our MSI MEG X570S Ace Max testbed, with 16GB of DDR4 RAM clocked at 3,000MHz operating in a dual-channel configuration. A 240mm water cooler was used to keep the processor from overheating, and an Nvidia GeForce GTX 3080 Ti graphics card operating at reference clock speeds handled the gaming benchmarks.
Right out of the gate, the Ryzen 7 5800X3D is up against some serious competition. The original Ryzen 7 5800X has less cache, but slightly higher clock speeds that should help it perform better in any tests that aren't able to take advantage of the jumbo cache. While the Ryzen 7 5800X and Ryzen 7 5800X3D carry the same $449 retail price, the 5800X is available for significantly less (it can currently be picked up from Amazon for $339). The slightly slower but even more affordable Ryzen 7 5700X also has similar overall specs to both of these processors.
It's also important to note that, unlike the 5700X and 5800X, the Ryzen 7 5800X3D is not overclockable to any significant degree. You can make small adjustments to the CPU by raising its base clock (BCLK), but anything beyond a tiny tweak will destabilize the system. The CPU's core multiplier is locked, as are all of its voltage controls, so you can't overclock the 5800X3D to match the Ryzen 7 5800X in clock speed.
Intel's 12th Generation "Alder Lake" processors are also a serious force to be reckoned with. Intel is far less generous in the cache department, but thanks to a greater number of cores and threads and their use of DDR5 memory, these chips have performed exceptionally well in our tests. Both the Core i7-12700K and Core i5-12600K are also priced well below the Ryzen 7 5800X3D.
The Ryzen 7 5800X3D soundly outperformed the 5800X and 5700X in most of our productivity tests. The performance advantage wasn't huge—certainly not big enough, in our opinion, to overlook the older chips' lower street prices—but the new CPU's edge was consistent.
Comparisons with Intel's "Alder Lake" processors are less promising, though. Only in our Handbrake and POV-Ray benchmarks did the Ryzen 7 5800X3D score a decisive win against the blue team. It managed to beat the Core i5-12600K in our 7-Zip and Adobe Premiere tests, but lost to the Core i7-12700K.
When it came to our graphics benchmarks, the Ryzen 7 5800X3D had mixed results. We tested the chip in three games and in 3DMark Time Spy, with our RTX 3080 Ti handling the graphics...
A clear picture emerged that showed the new AMD chip pulling ahead in games that ran into the hundreds of frames per second range. When running Rainbow Six Siege at 1080p resolution with high graphics settings, for example, the Ryzen 7 5800X3D set a new PC Labs record at 512fps.
When we hiked screen resolution to 4K, the test scores moved closer together as the GPU began to be the bottleneck, not the CPUs, at lower frame rates. Indeed as our scores show, the Ryzen 7 5800X3D and the rest of the field are close enough at 4K with the RTX 3080 Ti as to be indistinguishable on frame rates.
We witnessed similar results in F1 2020, with the Ryzen 7 5800X3D outrunning the pack at 1080p and the field tightening way up at 4K. In Assassin's Creed Valhalla, our GeForce RTX 3080 Ti hits its limits much earlier than with the other games in our suite, with even the best CPUs peaking at 110fps to 120fps at 1080p resolution. The Ryzen 7 5800X3D didn't lead the way in that game. As ever, some games will show a greater delta than others, depending on how and how much they lean on the CPU.
Esports Is the Main Beneficiary
Based on these results, we're left with the conclusion that the Ryzen 7 5800X3D's king-sized cache proves its mettle mainly at ultra-high frame rates. If you have a high-end GPU and a high-refresh-rate monitor, and love playing esports titles like Rainbow Six Siege at 1080p, you'll likely be thrilled with the new chip—although few gaming monitors can operate at 300Hz, and none that we know of can exceed 400Hz, which makes the CPU's ability to push frame rates past 300fps not particularly practical.
We suspect if you're gaming at more mainstream frame rates with a 120Hz or 144Hz monitor, you'll see little or no real-world benefit from the Ryzen 7 5800X3D even in esports titles. Judging by our tests, you're actually likely to fare worse than if you'd saved some money, bought a Ryzen 7 5800X or Core i7-12700K, and applied the extra bucks to a better GPU (if you happen to be buying one at the same time).
If you're wondering why the Ryzen 7 5800X3D trailed the 5800X in some of our tests, it's probably due to its lower clock speed and also partly due to the extra heat generated by the 3D V-Cache strapped to it. A clear implication is that the benefits of the extra cache often don't outweigh the higher cost.
One important detail we should note, however, is that the performance you'll see with the Ryzen 7 5800X3D will likely vary greatly in different games. The performance advantage of the 5800X3D was observable here in two of our game tests at 1080p, but not in the other game tests. In AMD's briefing on the 5800X3D, they showed that some games would see a major benefit from the added 3D V-Cache, whereas other games would see more modest results (as we did here). In other words, whether the Ryzen 7 5800X3D will benefit you will depend heavily on which specific games you play with it.
A Sideline: Gaming Tests With DDR4 3,600MHz
After consulting with AMD about our test results, AMD suggested we retest using DDR4 RAM clocked at 3,600MHz, as its technical personnel predicted this would improve the results for the Ryzen 7 5800X3D. Lacking the time before this chip's launch to retest all of the processors in the charts above with DDR4 RAM clocked at 3,600MHz, we instead did some last-minute testing with just the Ryzen 7 5800X3D and the Ryzen 7 5700X. To perform these tests, we needed to change the RAM used in the system from the 2x8GB (16GB) HyperX RAM kit that we were using that operates at 3,000MHz with CAS latency of 16 to a faster 2x8GB (16GB) Corsair kit that can operate at 3,600MHz with CAS latency of 18.
In the chart above, you can see the practical impact of switching from DDR4 3,000MHz to DDR4 3,600MHz in our test games. The Intel Core i5-12600K and Core i7-12700K were included here for comparison purposes, but both of those were tested with DDR5 RAM and not DDR4.
Ultimately, the faster RAM proved more beneficial to the Ryzen 7 5700X than it did the Ryzen 7 5800X3D. With its large pool of L3 cache, the Ryzen 7 5800X3D appeared less affected by RAM speeds, which makes sense as it doesn't need to fetch data from the RAM quite as frequently as the Ryzen 7 5700X would have to.
The Ryzen 7 5800X3D did see some performance gains, albeit relatively slim ones. It also saw a tiny performance drop in Assassin's Creed: Valhalla at 4K, which was consistent through multiple tests. In most tests, we noted no change or a small increase for the Ryzen 7 5800X3D overall, with the biggest increase being a 2.6% uptick in Rainbow Six: Siege at 4K.
At the same time, however, the Ryzen 7 5800X3D's lead over the Ryzen 7 5700X shrank in F1 2020 and in Rainbow Six: Siege at 1080p. Instead of the 5% advantage the Ryzen 7 5800X3D held over the Ryzen 7 5700X in F1 2020 at 1080p, that advantage is now a practically nonexistent 0.7%. The lesson here appears to be that, if you happen to be buying both chip and DDR4 at the same time, it might be more beneficial to buy a more affordable CPU like the Ryzen 7 5700X and pair it with faster RAM than to buy the Ryzen 7 5800X3D with slower RAM. This assumes the 5800X3D sells for list price and the older Ryzen 7s stay available at more than $100 less.
Verdict: A Battle Playing Out in the Street (Prices)
AMD has touted the Ryzen 7 5800X3D as its best gaming processor to date, but this was borne out in our benchmarks only at exceedingly high 1080p frame rates. It's certainly no slouch in other scenarios but it's not dominant enough in the games we tested to make it a clear victor given the launch list price.
And that's the biggest part of the puzzle, the one that makes this such an enigma chip: the Ryzen 7 5800X3D's steep price. Graphics card prices are still heavily inflated, but if you take the $100 or $110 you'd save by buying a Ryzen 7 5800X at current online prices and add it to your GPU budget, you could end up with a more potent system. (That is, of course, assuming you can get a step up in graphics card for that amount, but based on current market conditions you probably can.)
There's a small silver lining to the Ryzen 7 5800X3D in that it might have promise in a productivity or content creation PC. The new CPU's best test results came in creative apps like Blender and Adobe Premiere. Even there, however, its price needs to come down a bit to better compete.
AMD's premium-priced Ryzen 7 5800X3D is a solid eight-core performer, but its boosts to game pep and CPU-specific performance can't quite offset the cost bump.
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