AMD’s 3D V-Cache Secret: Why No Dual-Stacked X3D Processor on Both CCDs
Ryzen 9 9950X3D and 9900X3D: The Future of Gaming CPUs?
In the realm of computer hardware, AMD’s recent announcement of the Ryzen 9 9950X3D and 9900X3D processors has sent shockwaves through the industry. Announced at CES 2025, these CPUs build upon the success of their 7000-series counterparts, featuring two Core Complex Dies (CCDs) with a twist – only one of the two CCDs has 3D V-Cache stacked underneath or on top, leaving enthusiasts wondering why this might be the case.
According to HardwareLuxx, AMD revealed to them that the reason for this design choice is not due to technical limitations, but rather purely economic. The company claims that a processor with two CCDs and 3D V-Cache on each would be "too expensive, and games would not benefit from a second CCD with 3D V-Cache to the same extent as the step from 32 to 96 MB L3 cache for one CCD."
This unique design decision aims to streamline performance and improve gaming capabilities while keeping costs in check. The Ryzen 9 9900X3D and 9950X3D have two CCDs, with the former featuring six cores per CCD and the latter having eight cores per CCD. However, the 3D V-Cache is situated only underneath one of these chiplets, which means the top-end 9950X3D has the same 64 MB of 3D V-Cache as the 9800X3D and only eight of its cores have access to it.
This configuration offers a twofold benefit. First, the cores on the CCD without the chiplet can boost to a higher clock speed. Second, there are more cores available, making the 9950X3D suitable for applications that require numerous multicore performance. Crucially, the 9950X3D should deliver similar gaming performance to the 9800X3D, thanks to its eight cores with access to 64 MB of 3D V-Cache.
However, the performance outcome will depend on how well software handles core scheduling between those with access to 3D V-Cache and faster cores that lack such access. This can lead to issues, as seen in the 7900X3D and 7950X3D.
What’s Next for Gaming CPUs?
Is this the end of the road for gaming CPUs in terms of 3D V-Cache capacity? Not necessarily. While it’s true that games may not benefit directly from additional 3D V-Cache capacity, other applications can. For instance, applications with more complex thread scheduling and higher Multithreading requirements could greatly benefit from 192 MB of L3 cache with 16 cores.
AMD has made a calculated decision to prioritize a single-stacked 3D V-Cache design, deeming it the most cost-effective and practical choice for their current product line. As the hardware landscape evolves, it’s possible that future innovations may lead to variations of this design, offering more comprehensive cache solutions for demanding applications.
Stay tuned for more insights and updates on the AMD Ryzen 9 9950X3D and 9900X3D, as well as the latest developments in the world of computer hardware.
