Ryzen 7 5800X3D vs Ryzen 9 5900X

Last Updated: March 3, 2022

AMD Ryzen 7 5800X3D vs Ryzen 9 5900X. Which is better? It’s a question I’m sure you’ve asked yourself on the approach to the 5800X3D release date. AMD announced its rehash of Zen 3 desktop CPUs last year and knowing that the new Ryzen 7000 series would fall under AM5 there was some confusion around what exactly the Zen 3 rehash was until AMD announced the 5800X3D later on in the year. 

The Ryzen 7 5800X3D is a brand new 5000 series CPU and likely the last to support the AM4 platform. AMD recently added the full specifications of the 5800X3D to its website so we can take an in-depth look at the on-paper specifications. With AMD claiming the 5800X3D is capable of outperforming the 5900X and the 12900K from team blue, and with a price confirmation yet to be seen, it leaves one question – will it be worth the upgrade? 

If you’d like to know more about Zen 4 or the up and coming AM5 socket, we have comprehensive articles on them.

Cache and 3D v-cache 

The most notable difference between the 5800X3D and the 5900X is the cache type. 

What is Cache?

Briefly, cache serves as a system memory extension and is constructed close to CPU cores for speed and efficiency. Cache in today’s modern CPUs comes in three levels. 

Level one cache is the fastest but also the smallest, and is reserved for integral operations. Level two cache is a middle ground between L1 and L3 cache, with the second-fastest speed and second fastest storage. Finally, level three cache is the largest but also the slowest cache type, reserved for frequently accessed file paths to speed up the usage of regular programs. 

Note that when we say slow we still mean magnitudes faster than general RAM, just much slower than L1 cache. 

5800X3D vs 5900X: 3D cache vs 2D cache 

The new 5800X3D offers a new 3D cache while the 5900X reserves the 2D cache structure. 

3D cache dies are stacked vertically instead of laterally. This is beneficial and allows for a much larger capacity in the exact same footprint. Since the 2D cache inside the 5900X is stacked laterally, the dies require much more space and are therefore limited by the space they occupy. 

To put it very simply, stacking cache vertically allows for much faster access speeds and aids the acquisition of instructions, allowing the CPU to be fed more quickly.  

We have far more detail on the new cache type of the 5800X3D in our ‘5800X vs 5800X3D’ article if you want to know more. 

Ryzen 7 5800X3D vs Ryzen 9 5900X: specifications

When comparing two components it’s important to outline the specifications to determine how good they are, how they might perform and how they stack up against each other on paper. Some examples of CPU specifications would be core count, cache size and core speed. We will compare the specifications of both the AMD 5800X3D and the 5900X.

5800X3D

The Ryxen 7 5800X3D is a brand new CPU on the new Zen 3 rehash. The 5800X3D will be bringing with it a brand new 3D cache to help vastly improve the cache capacity whilst retaining access speeds. We have seen projections against AMD and Intel’s current flagship CPUs (5900X and 12900K) and from where we sit it looks like a favourable contender. 

The specs of the Ryzen 7 5800X3D are as follows: 

5900X 

The Ryzen 9 5900x belongs to the Ryzen 9 family of AMD CPUs, and are among the most powerful desktop processors AMD has to offer (besides the Threadripper line of CPUs which is a different beast entirely). The 5900x blew away its predecessor, the 3900x, in many ways, including clock speed, cache and support. 

The specs of the Ryzen 9 5900x are as follows:

5800X3D vs 5900X: specification comparison

Here we will compare the on-paper specifications of the Ryzen 7 5800X3D and the Ryzen 9 5900X and pit them head-to-head. This should help us make an informed decision when deciding on our next CPU upgrade. 

Core count 

The AMD 5900X has a higher core count than the 5800X3D. 

A higher core count means the CPU will be superior at multitasking natively as more of the day-to-day processes can be handled by the CPU at any given time. However, it all depends on whether the software you are using has multicore support baked in. Some older applications and games do not have this support and are unable to leverage the CPU’s extra cores. 

Not to worry though, most modern games or programs utilize at least four cores, with workstation and rendering applications able to utilize many more. So if you’re building a server or a workstation, cores are the way to go. 

Thread count 

The 5900X has more threads than the 5800X3D.

Threads can be thought of as cores, only they occupy no physical space and are forced to share resources with physical cores, making them slightly slower as a result. What do we mean by physical cores? 

Physical cores are cores that occupy a physical space on the CPU die, hence the name. Threads are the CPU core’s ability to process two instructions at once through a process AMD dubbed SMT (Simultaneous Multithreading).

This means that each CPU core is now able to process two instructions simultaneously, through one physical core and one virtual thread. So, for workstation purposes much like core count, it’s better to have more. 

This was an incredibly summarised version of SMT and you can explore our ‘What is SMT’ article to learn more. 

Core speed 

The 5900X has a higher core speed than the 5800X3D. The Ryzen 9 5900x boasts a boost speed of 4.8GHz and the Ryzen 7 5800X3D gives us a boost speed of 4.5GHz. 

Core speed is important for instructions and IPC (instructions per cycle). This is the number of instructions a CPU can execute every CPU cycle. This refers to the instruction cycle that consists of fetch, decode and execute actions. 

A CPU clock speed is how many instruction cycles a CPU can perform every second and since it’s measured in gigahertz we’re talking about billions of instructions. Not all core speed was created equal, however. If a CPU belongs to an architecture with a smaller nm process like 10 vs 12, the 10 nm process will have a higher IPC as the transistors used in its composition are smaller, meaning more are present. 

This suggests that CPUs with smaller transistors allow the CPU to fit more into one space, meaning the CPU with a 10nm process is capable of more computations per cycle. This means that one of the 10nm process CPUs cycles is worth more than one of the 12nm process CPU cycles. 

So, even if both CPUs had the exact same clock speed, the CPU with the 10nm process would be more powerful as it has a higher IPC. 

There’s a lot to take in here – IPC, core speed, CPU cycle. We explain these subjects in far more detail in our ‘5800X vs 5800X3D’ article. 

Cache 

Surprisingly, the 5800X3D has a larger total cache of 94MB than the 5900X despite it’s fewer cores. 

Cache, as we outlined earlier, is the extension of a system’s memory and comes in three levels on today’s CPUs – L1, L2 and L3 cache.

Besides the differences between 2D and 3D cache, both types serve the same purpose and that is to improve instruction access and execution speeds. Doing so increases CPU performance overall. A CPU cache is constructed close to CPU cores and reliably improves access speeds as a result. 

Compared to RAM, the three levels of CPU cache are blisteringly fast, and each level has different applications and plays a different role in the CPU cycle. 

Level one cache is the smallest capacity and has the fastest speeds. This is where crucial CPU instructions are stored for faster access speeds. 

Level two is a nice middle ground between L1 and L3, with medium capacity and medium speeds. This is where less crucial CPU instructions are stored but will still benefit from fast access speeds. 

Level three has the highest capacity and is much slower in comparison to the other levels (but still fast compared to RAM). This is where frequently used paths like application paths are stored to give your CPU a boost when accessing frequently used data. 

TDP

Both CPUs on our list have the same TDP of 105W.

TDP or thermal design power is the maximum amount of heat energy a component can output under normal operating conditions. All you need do is pair this CPU with a cooler that can comfortably dissipate more than 105W of thermal energy. 

This is the energy transferred under normal conditions, though, we aren’t speaking about overclocking. Overclocking drastically increases a component’s TDP due to the presence of extra voltage or more strenuous operating conditions. For this reason, if you plan on overclocking either of these components, you should consider getting a cooler that drastically exceeds the 105W TDP requirement. 

Socket 

Both of our CPUs fit into the same AM4 socket. 

AM4 is currently the socket of choice for AMD gamers, but not for long. With AM5 on the horizon, that’s one of the factors you need to take into consideration. As we mentioned previously in this article, this Zen 3 rehash is likely to be the last to see the AM4 platform.

AM4 currently is based on PGA (pin grid array) and AMD has managed to keep this socket running for over five years. However, it’s now starting to show its technical limitations based on the claims of advanced AM5 specification showcases. 

5800X3D vs 5900X: results 

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