Why does AMD make its Ryzen 7000X3D with an asymmetric design?

We are just a few days away from finally knowing the performance of the new Ryzen 7000X3D, those that are destined to dominate the gaming market over Core 13. But, curiously, there is something that is being talked about lately that has not a correct approach, or at least a specific one. We refer to asymmetric design that AMD has adopted with these Ryzen 7000X3D and its 3D V-Cache. Why make them like this and not put two SRAM dies on each CCD? Well, because, in theory, thus they would lose performance.

And it is that those of Lisa Su have learned from the lesson that was the already famous Ryzen 7 5800X3D, one of the best CPUs in performance per FPS and euro invested. We say this because this processor, despite being very fast in gaming, offered lower performance in other titles due to something that AMD tries to alleviate with these new models with 3D V-Cache.

The reasons why AMD would have designed some Ryzen 7000X3D asymmetrically

The other day we saw that the 7800X3D will arrive with higher frequencies than the Ryzen 7950X3D and it was speculated that the former could be faster than the latter, despite having fewer cores. The problem is that this speculation did not count on asymmetry.

Of the two CCDs, only one will have the 64 MB vertical cache, where the logical thing was to have used two 32 MB dies to place them on top of each one of them. It was speculated that costs would be reduced by using a single silicon instead of two, but although this is largely true, the main reason would be another.

And it is just covering two different scenarios where the already veteran Ryzen 7 5800X3D could not do it: games that are highly dependent on the cache and games that are not dependent on the cache at all. What does this imply?

The 3D V-Cache and the common L3 cache

In Triple A games, the amount of data, Esports Extras positioning and technologies to be processed by the game engine, the API and the different parts of the hardware involved make adding a larger L3 cache very beneficial so as not to have to request addresses from memory to RAM, the main bottleneck right now on PCs and servers.

But this only happens with very demanding games, whereas with the so-called e-Sports this does not happen. They are light games, prepared for hardware with little performance and, above all, they benefit from higher clocks.

With the Ryzen 7000X3D with two CCDs, that is, 7900X3D and 7950X3D AMD covers both sectors of gaming, the main reason why the 5800X3D did not come out on top in many reviews and was surpassed by its brother without 3D V-Cache. AMD’s move is more than smart, It is brilliantand we explained.

The priority and assignment of tasks and processes using Windows and AMD driver

In very demanding games the Windows kernel process manager (supported by driver and firmware/priority algorithms and Branch Prediction) will send the load to CCD with 3D V-Cache, but if it simply requires processing as fast as possible, it will send it to the CCD without the vertical cache, which logically has a higher clock. This also involves the SMT wires as seen in the top slide of the Front End for the general architecture.

Giving an empirical example, COD: MW2 and its processes will go first of all to the CCD with 3D V-Cache and then it will take over the rest of the other CCD, always prioritizing the first one.

Instead, CS:GO will do the opposite and will go first to the CCD with higher clock, boosting performance and not leaving those cores as it does not need more power to work the data by the processor. Therefore, the performance will be the best in both scenarios and for this reason, at least on paper, the Ryzen 7 7800X3D should not outperform its older brothers in a battery of tests. well balanced.

Now, and having said that, if that battery of games only includes very new and graphically intensive titles as well as high CPU dependency, yes, it is possible that it equals them and at some point surpasses themsomething that we will see from next Monday with the reviews and the details of the architecture.