Introduction :
When comparing processors like AMD’s Ryzen 9 7950X3D and Ryzen 7 7800X3D, it’s natural to assume that the higher-end model with the more cores will perform better in all areas. However, in the world of video games, this logic doesn’t always apply. Surprisingly, the 7800X3D can outperform the 7950X3D in many gaming scenarios. Let’s take a closer look at the reasons behind this phenomenon.
Understanding the architecture of the two processors :
The Ryzen 9 7950X3D is a high-end processor, based on the Zen 4 architecture, with 16 cores and 32 threads. The special feature of the Ryzen 9 is its chip design, divided into two CCDs. A CCD (Core Complex Die) is a grouping of cores. It can have 6 cores or 8 cores.
The 7950x3d is equipped with 2 CCDs, each with 8 cores. By way of comparison, the Ryzen 7 7800X3D has 8 cores and 16 threads, which are grouped together in a single CCD, fully equipped with 3D V-Cache, which reduces the complexity of the chip.
The importance of 3D V-Cache in gaming performance :
3D V-Cache is a technology that adds an extra layer of L3 cache to the processor. By allowing the processor to keep more data in cache, 3D V-Cache reduces the number of round trips to RAM, speeding up information processing. It also makes chips with x3D technology less dependent on RAM frequencies than their versions without 3D cache, as the extra cache acts as a kind of RAM booster. In-game, x3D chips can store more data, reducing cache misses and the need for frequent memory access. This translates into an overall performance gain for the game.
Why the Ryzen 7800X3D can outperform the 7950X3D in games :
1. Uniform cache access
As you can see from the photo above, the 7800X3D has a single 8-core CCD with 3D V-Cache. As for the 7950X3D, only the first 8-core CCD benefits from 3D V-Cache, while the 8 cores on the other CCD only have a standard 32 MB L3 cache.
2. Thread management complexity
One of the main problems with the 7950X3D is the Windows System Scheduler. To optimise performance, the system needs to direct tasks to the right CCD. For gaming tasks, it should use the cores equipped with 3D V-Cache and for professional tasks, the CCD with the cores not equipped with 3D V-Cache. The latter is preferable, as it gains in raw performance thanks to higher frequencies. However, the problem is that Windows is not very good at directing tasks to the right CCD. The system uses the Game Bar to define core usage, but this process is poorly managed. Windows gets confused and allocates the wrong cores in most situations.
For example, in games, the scheduler often uses non-X3D cores instead of X3D cores, resulting in a loss of performance in your games. The need to manage two different types of cores adds complexity that can introduce latency, crashes, etc. in certain scenarios.
3. Clock frequencies and thermal impact
One of the problems is that clock frequencies are reduced on cores with 3D V-Cache. This is due to the fact that the cache is located above the cores on these processors. This extra layer complicates heat exchange between the cores and therefore increases heating. To control the heat generated, these cores operate at slightly lower frequencies and voltages. What’s more, X3D models are not manually overclockable, and you can only use the PBO (Precision Boost Overdrive) to improve performance. This is one of the things AMD has put in place to limit the risks on these chips.
As you can see, the cache is both an advantage and a constraint for the processor. As a reminder, at the start of the 7000X3D generation, we saw problems with CPUs burning up because, being more sensitive to voltage, they overheated. The problem was quickly resolved and, since then, there have been no more problems thanks to increased limitation of the amount of voltage injected into the CPU.
4. Optimising games for the number of cores
Most games today are optimised to run on 4 to 8 cores. Beyond that, performance gains are minimal. As a result, the 16 cores of the 7950X3D are not fully exploited in games, which means that the extra cores don’t bring any great benefit.
5. Inter-CCD latency
Communications between the CCDs are an important factor to consider. On the 7950X3D, data sometimes has to pass between the two CCDs, which introduces additional latency.
In contrast, the 7800X3D, with its single CCD, avoids this latency, offering faster response times. Tests and benchmarks carried out by various specialist websites have shown that the 7800X3D often offers slightly higher or more stable FPS rates in games than the 7950X3D, particularly in games that are very sensitive to latency.
It’s also important to note that while a larger cache can improve performance in games, it also introduces additional latency. For example, X3D processors, equipped with a larger L3 cache thanks to 3D V-Cache, have a higher latency than non-X3D processors.
When is the 7950X3D better than the 7800X3D?
For tasks such as 3D rendering, video editing, modelling, or intensive calculations that can take advantage of 16 cores, the 7950X3D will far outperform the 7800X3D. If you’re running several heavy applications simultaneously, the extra cores may offer better responsiveness. However, for traditional use limited to games, it offers no advantage, so the 7800x3D is more attractive because it’s cheaper and consumes less power.
Conclusion:
To sum up, the choice between the Ryzen 9 7950X3D and the Ryzen 7 7800X3D mainly depends on how you plan to use it. For gamers, the 7800X3D is often the better choice, offering superior gaming performance thanks to its 3D V-Cache on all cores and a simpler architecture. Its power consumption and price are another argument against its big brother or other competitors.
For professionals with multi-purpose applications including gaming, the 7950X3D makes full use of its 16 cores in professional applications, offering more raw computing power than the 7800X3D. Although it performs well in games on paper thanks to an 8-core CCD equipped with 3D V-Cache, its dual CCD design – one with cache and the other without – makes it difficult to optimise, which means it performs less well in games than the 7800X3D.
In the end, even though the 7950X3D is a more powerful processor on paper, the 7800X3D can offer superior performance in games because of its design optimised for these specific tasks.
