One of the most interesting novelties of Computex 2021 was undoubtedly the AMD’s 3D V-Cache technology, with which the company has shown us its ability to increase the cache on board processors by stacking it on top of the computing chips.
The US company discussed this innovation using the prototype of a suitably modified Ryzen 9 5900X, and at first it was not clear if the product was going to hit the market or if it was just a demonstration. During the event, AMD spoke generically of a production set for the end of the year, without however clarifying with which architecture.
In the following hours, AMD confirmed that from the prototype we will move on to a concrete product, that is we will see Ryzen CPUs based on Zen 3 architecture, such as the current Ryzen 5000, improved by 3D V-Cache technology which will give them more cache. Given the production set for the end of the year, it is likely that we will have to wait until the beginning of 2022 to see these products on the market, before any solution based on Zen 4 architecture (for which we are talking about the end of 2022).
Among the other details that emerged regarding 3D V-Cache we find the interesting information that the additional 64 MB of L3 cache conferred on each CCD on the processor (which add up to the 32 MB integrated in each CCD) can potentially be increased up to 512 MB: in this first implementation of the technology we have in fact a single cache stack, while potentially it is possible to push fino a 8 stack (each stack currently offers 64 MB of additional cache).
Another important aspect for energy efficiency is the ability to completely turn off the cache when not in use, while the impact on temperatures should be negligible, as SRAM does not disperse a large amount of heat. The same goes for consumption.
Furthermore, the Zen 3 CCD is already prepared for 3D V-Cache and all the control and power logic is in the CCD. There should be no significant impact on the latency front, AMD also assures using the additional cache will not require any software changes.
AMD’s new Ryzen CPUs with 3D V-Cache will go to clash with Intel Alder Lake solutions characterized by a hybrid architecture (high performance and low consumption core together, in the big.LITTLE ARM style).
The Ryzen 9 5900X prototype with 3D V-Cache technology manages to deliver 15% higher performance on average in 1080p gaming, with peaks of 25%, compared to a classic Ryzen 9 5900X, so it will not be easy for Intel to deal with this project, which introduces a leap in performance that is typically obtained with an architectural renewal.