Ryzen 9 9900X vs. Ryzen 9 7900X: two powerhouse of different generations, what’s the difference?

With AMD announcing the launch of the Ryzen 9000 processors at the end of July, we’re all in the same boat: We wonder how much more powerful they’ll be compared to the competition and previous generations. 

It is normal practice to pit processors of different generations against each other, such as mid-range vs. mid-range, but in this article, we’ll explore how the high-end processor of the 7000 series, the Ryzen 9 7900X, fares against the behemoth, the Ryzen 9 9900X. So, without wasting another moment, let’s get right into it.  

AMD Ryzen 9 9900X

Cores

12

Threads

24

Boost clock speed

5.6 GHz

Base clock speed

4.4 GHz

L3 Cache

64 MB

TDP

120 W

Platform

AMD Socket AM5

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AMD Ryzen 9 7900X

Cores

12

Threads

24

Boost clock speed

5.6 GHz

Base clock speed

4.7 GHz

L3 Cache

64 MB

TDP

170 W

Platform

AMD Socket AM5

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Specifications

To see the hardware difference between the two processors, we’ve listed their specifications below.

Looking at the on-paper specifications, we can see that the 9900X has the advantage with its newer architecture and much lower TDP, but we’ll dive deeper to explore what this difference means. 

Foundations and cores 

The 9900X and 7900X are based on the AM5 platform, meaning they use the LGA socket type. The main difference between them is their architecture. The former has a 4nm CPU process technology powering its operation, while the latter isn’t far behind with a 5nm CPU process.

However, on a physical level, a 1nm decrease in size means many more transistors fitting on each core, which should give the 9900X lead in performance and efficiency. To put things into perspective, the 7900X has a transistor count of 13,140 million with 5nm processes. 

While you may think that a 1nm size difference won’t mean a lot, the 5900X has a transistor count of 8,300 million with 7nm processes. So, we could potentially see the 9900X with a transistor count anywhere from 15 – 17 million. However, this is just a rough guess, and we’ll have to wait for the official release to be sure. 

Both processors have the same number of cores and threads but run at different speeds, which we’ll explore in the next section. 

Clock speed

The boost clock speed of both processors is the same, while the 7900X has a 0.3 GHz lead in the base clock speed. That said, the 9900X has more transistors running than the 7900X, meaning it should be able to complete more instruction cycles per second, resulting in better performance across the board.

However, the 7900X is no slouch. We put it through its paces in our 7900X review, and it performed amazingly in real-world and synthetic tests. It scored 2,017 and 28,006 points in Cinebenck R23 single- and multi-core tests, respectively. To put things into perspective, it outperformed the best averages of the Ryzen 9 7900X3D, which we’ve reviewed, and Team Blue’s 12900K. 

Cache and TDP

Both AM5 processors share the same 64 MB L3 cache size, but the TDP is where it takes a turn. The 7900X has a 50W higher TDP than the 9900X, with a 170W power draw against 120W. But considering the architecture difference, it makes sense since smaller transistors are more energy efficient. That said, this should give you an idea of how big a difference 1nm makes. 

So, the 9900X takes the win in this section, as it should be able to use the 64 MB cache more effectively and consume less power.  

Graphic capabilities

The Ryzen 9 7900X and 9900X both come with integrated graphics. This internal GPU has a turbo frequency of 2200 MHz and two cores. It isn’t as impressive as a dedicated GPU, but it should be enough to boot your system and perform some basic tasks, such as using the Microsoft Office suite or browsing the Internet. 

For next-level gaming performance, we recommend pairing the 7000 series CPU with the best GPU for 7900X. 

Pricing estimates

While we can’t be sure how much the Ryzen 9 9900X will cost as we have to wait until 31 July for its release, we know how much the 7900X went for at launch and its current price. This should give us an idea and allow us to make an informative guess. 

The 7900X was released in 2022 with an MSRP of $549. Right now, according to Camelcamelcamel, you can get it for as low as $360, which is a $189 price reduction. The 5900X also launched with the same MSRP, so we believe the 9900X should cost around $549 or $599.  

How have these CPUs changed from the previous generations?

We can see in the table above that the “900X” processors have the same core count, threads, and cache. Where they differ is their architecture, TDP, and clock speeds. 

The 9900X has the highest and similar boost clock speeds as the 7900X, while the 7900X takes over with the highest base clock speed. It isn’t surprising to see that the clock speeds reduce as we go down the generations. 

The TDP, however, has a big gap as the 7900X consumes 50W and 65W more than the 9900X and 5900X and 3900X, respectively. One would assume that the 5900X would have a higher power draw due to its larger CPU process size, but that isn’t the case. 

However, it’s nice to see AMD controlling the power draw with their latest CPUs, which should give more overhead for overclocking and enable you to power your setup with a budget PSU. If you’re interested in exploring some options, we recommend you check out our best power supplies guide for the top picks.  

Alternatives to the 9900X and the 7900X

There are some processors that you could opt for instead of the 9900X and the 7900X, and we’ve listed them below. We’ve reviewed some of these alternative options, and you can also check out their in-depth reviews.

Which one is right for you? 

There is no correct answer to this question, as each individual has different budget constraints, workflows to take care of, and situations they’re dealing with. That said, whether you should go for the powerful Zen 5 9900X or the previous powerhouse, the 9700X, depends on how much you can spend and whether your work requires an upgrade.

Both processors bring excellent features and should be able to use modern motherboards to their full extent. However, we might see a price reduction for the 7900X when the 9900X is released, so if you don’t want to spend extra money on an upgrade, the 7900X is an excellent processor and by no means underpowered. It should be able to handle rigorous gaming and productive sessions alike. 

I reached out to Jack Howarth and Seb Kozlowsk, our resident hardware experts and tech enthusiasts, and once again, we were all on the same page.

The Ryzen 9 9900X proves to be more powerful and more efficient by default, thanks to the uplifts in performance that the Zen 5 cores bring, However, you will pay full price.

If you’re looking for something that still has a lot of power under it’s IHS, will be a little lighter on the wallet, and is by no means obsolete, than you could enjoy the fruits of the 7900X.

No matter which CPU you choose, you will be able to enjoy them on the same platform, as the release of the 800 series motherboards loom, it’s important to remember that both CPUs can take advantage of the features it offers

Jack Howarth

Both Ryzen 9’s have plenty to offer for your build. Coming in with 12 cores, they’re a great use case for those running heavy and multi threaded tasks. Being on the same platform of AM5 they have the same build possibilities and components to support them. But primarily, the 9900X has the benefits of a better foundry process, improving its transistor count but also dropping the power requirements. So it should improve in performance but running it will be cheaper as you might find yourself paying more for it as the newer processor initially.

Seb Kozlowski