AMD Ryzen 9 7950X3D With 2X 3D V-Cache Upgrade Spotted In The Wild

ryzen 7 7950x3d delid
AMD's Ryzen 9 desktop processors include two "Core Complex Dice", or "CCDs", which is to say that the processors' 12 or 16 CPU cores are spread across two pieces of silicon. The company's top 3D V-Cache-equipped CPU, the Ryzen 9 7950X3D, is known for only including 3D V-Cache on one of its two CCDs.

In theory, this should be a bonus, as it allows the chip to have some cores that clock higher than is possible with 3D V-Cache, and still have another eight cores equipped with the extra cache. That way, it can cater to workloads that mainly benefit from high clocks or big caches—but in practice, it can be tedious to manage.

If you're mainly gaming, you're basically always going to want everything to run on the 3D V-Cache CCD. Wouldn't it be nice if AMD sold such a chip? For its part, AMD says that it doesn't sell a chip with that configuration as, apparently, the extra L3 cache somewhat negates the benefit of having such a big cache by increasing access latency.

bilibili 7950x3d 192mb cpu
Image: Bilibili via HXL (@9550pro on Xwitter)

Nevertheless, a user on Bilibili claims to have exactly such a CPU. In a short video titled "Unbelievable! My AMD CPU has 64MB more cache than it's supposed to" (spotted by HXL), the user "也许是P某" ("Maybe it's P") clearly shows both the Windows Task Manager as well as CPU-Z indicating that the processor is equipped with 192 MB of L3 cache. That would line up exactly with two Zen 4 CCDs, each sporting a 64MB 3D V-Cache die.

instlatx64 cpuid bug

So, is that what we're looking at? Probably not, sadly. As well-known programmer and analyst InstLatX64 notes, there is a documented issue where checking the wrong CPUID location shows 192MB of L3 cache on 3D V-Cache-bearing Ryzen 9 CPUs. A patched Windows and updated CPU-Z shouldn't be showing these values, but it's possible that the user is using an older version of Windows 11 or possibly an older system firmware.

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The 7800X3D ultimately gives the best game performance. From our review.

While we find AMD's reason for not selling a "dual V-Cache" version of the Ryzen 9 7950X3D a bit curious—after all, the company sells Milan-X CPUs with extra cache on every single chiplet—the fact remains that games typically perform best on the Ryzen 7 7800X3D in any case. If you're buying a CPU primarily or strictly for gaming, stick with the eight-core model. You're not going to get anything from those extra cores in the vast majority of games.