AMD is reportedly preparing to bring 3D V-Cache technology to Zen 4 mobile CPUs! Chips with V-Cache have long been available for desktops and servers, but this is the first time it will be on an AMD mobile chip.

According to a tweet (or X or something) from @9550pro, the first chip is the Ryzen 9 7945HX3D. It will be in the upcoming Asus ROG Scar notebook. This chip has 16 Zen 4 cores and a total of 128MB of L3 cache. This is made up of 32 MB each in two chiplets and another 64 MB of stacked cache.

Since this chip is at the top end of AMD's mobile CPU series, it is expected to be found in flagship desktop replacement machines with the best GPUs. Battery life and mobility will not be selling points for these systems. It is quite possible that laptops with this chip will be the fastest on the market.

If the mobile V-Cache chip proves to be a success for AMD, there is no reason to doubt that the technology will trickle down to worldwide models. 8- or 6-core V-Cache-equipped chips should provide excellent gaming performance, and with any luck, AMD's mobile CPUs will not cost much and will have good battery life, which is a hallmark of mobile CPUs.

It is surprising that AMD has not released a V-Cache model for the notebook market. Given the nature of mobile chips, it is not surprising. They don't have the TDP or heat budget of desktop chips, and are clocked lower, so more L3 cache should be even more advantageous for games that need to gobble up power to maximize performance.

The Ryzen 9 7945HX without V-Cache has a default TDP of 55-75W, so there should be no concern about vulnerabilities in the TSV interconnect between the chiplet and cache. Overvoltage is the enemy of the V-Cache, and this concern is not present in low-voltage mobile chips.

How successful these chips will be depends on the rest of the system; V-Cache models cannot magically run GPU-limited games at 4K as fast, but they can help at lower resolutions in systems with very high refresh rate screens. It is unlikely that a system with a 7945HX3D, RTX 4090, and 1080p screen will be released, but at 1440p it is possible for a high-end GPU to achieve 240 FPS or more. Well-optimized esport games are one example, and in such use cases the X3D mobile chips should perform best.

Of course, stacked cache is not beneficial for all games and applications. when the L3 cache fills up, the system needs to fall back to system memory. how AMD can Turbo mode, chiplet software, drivers will be tuned to provide optimal performance for all types of mobile workloads will be interesting to see.