Pre-launch tests raise concerns about the performance of Ryzen processors with 3D V-Cache, but are they justified?
Two new AMD Ryzen 7000X3D V-Cache chips are scheduled to launch on the 28th: Ryzen 9 7900X3D and Ryzen 9 7950X3D. As per tradition, someone with access to one of these pre-launch chips accidentally uploaded the Geekbench 5 test results with some interesting results. Compared to the regular 7950X, the 7950X3D had comparable single-threaded performance and lower multi-threaded performance. This benchmark seems to show what to be concerned about with the Ryzen 7000X3D, but it shows the expected performance.
Let's not get hung up on how accurate the leaked benchmarks can be. We already expected the 7950X3D to lag behind the 7950X in some cases. 3D V-Cache technology allows AMD to add 64 MB of additional cache to the processor, but it's not without its downsides. Processors with V-Cache have thermal, power, and voltage limitations, which means clock speeds will have to drop from time to time. This isn't too much of an issue for single-threaded workloads that don't consume much power and don't generate a lot of heat, but it's definitely a problem for multi-threaded workloads, and the Geekbench 5 results clearly show this.
Another factor in this test is the usability of the V-Cache itself. The problem is that more cache doesn't always mean better performance, and Geekbench 5 isn't a workload that benefits much from more cache. Ryzen 3D V-Cache processors are primarily designed for higher frame rates in games and are much more memory and cache sensitive than most other applications. Depending on what your PC does or doesn't do, you won't see any benefit from V-Cache, and performance may be lower compared to non-X3D chips.
In 2022 we saw the same with the Ryzen 7 5800X3D, the first Ryzen CPU with V-Cache. It was slower than the regular Ryzen 7 5800X in clock speed-critical workloads, but in gaming, the 5800X3D was definitely the best processor to achieve high frame rates. This is probably why not everyone is confused about these Geekbench 5 results. Most comments on various articles and topics indicate that V-Cache reduces the frequency and improves performance only in some applications such as games.