https://arstechnica.com/gadgets/2022/04/review-ryzen-7-5800x…
AMD uses a unique packaging technology called “3D V-Cache” to triple the amount of L3 cache on the processor, from 32MB for the standard Ryzen 5800X to a whopping 96MB. This new tech feels like an experiment in some ways. Unlike other Ryzen CPUs, the 5800X3D doesn’t offer overclocking or power consumption controls, and its clock speeds are a bit lower than the standard 5800X. But AMD says that the extra cache allows the 5800X3D to outrun Intel’s fastest CPUs when it comes to gaming.
We’ve run some tests on the 5800X3D to find its strengths and weaknesses and to get a sense of when you’ll notice the impact of the additional cache. This is undoubtedly an interesting processor, but its pricing and extremely specific performance advantages will limit it to a niche of a niche.
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The 64MB of additional L3 cache, also built on TSMC’s 7 nm process, is physically stacked on the Zen 3 CCD and connected with direct copper-to-copper bonding. The result is something that the system sees as one large pool of L3 cache that can all be treated the same—the 64MB of stacked cache isn’t an L4 cache, and the 32MB of L3 cache built into the CCD doesn’t have any performance advantage compared to the cache stacked on top.
Copper-to-copper bonding is used to fuse the CCD and the additional cache together.
Enlarge / Copper-to-copper bonding is used to fuse the CCD and the additional cache together.
AMD
One side effect of this packaging technology is that the 5800X3D runs at a noticeably slower clock speed than the 5800X, and AMD doesn’t officially allow any overclocking or power adjustments when using the 5800X3D. AMD is pushing the 5800X3D mainly as a gaming processor, and that’s because games benefit more consistently from having a bigger pool of cache to play with. For workloads that care less about cache and more about clock speed—as we’ll see when we start benchmarking—the 5800X3D can be slower than the regular 5800X, which AMD freely admits.
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AMD played coy about whether we could expect future Zen 3 CPUs with 3D V-Cache enabled, but reading between the lines, it seems unlikely. 3D V-Cache will be one of the tools in AMD’s toolbox when it comes to boosting performance for Zen 4 and the first Socket AM5 platforms—along with a 5nm TSMC process, DDR5 support, and other architectural improvements—but I don’t get the sense that the 5800X3D will be followed up with an expanded lineup of Zen 3-based X3D chips.
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The Ryzen 7 5800X3D is probably best approached as a proof of concept rather than a CPU you should seriously consider for your next build.
AMD’s claims about performance are true, and it bodes well for the Ryzen 7000 series that adding extra L3 cache to the same old Zen 3 architecture can boost performance by this much in games and a few other tasks. As a tech showcase, it’s effective! And that AMD can still squeeze extra performance out of the aging AM4 socket is a testament to its versatility and longevity.
But you only really see the 5800X3D’s benefits when you’re trying to achieve extremely high framerates at relatively low resolutions. That’s fine if you’re trying to play games on a 240Hz monitor at 1080p. But at 1440p and 4K, your GPU will still usually be more important than your CPU. And for less money than the 5800X3D costs, you can get very good gaming performance along with more balanced CPU performance for creating content and doing other work.