AMD Ryzen 9 9900X vs Ryzen 9 7900X: What's the difference?

As the final quarter of 2024 rolls into view, the industry is winding up to deliver plenty of new releases, and AMD is leading the pack with the Ryzen 9 9900X and Ryzen 9 7900X. Now, we know what you’re thinking: “Damn, those are some big numbers, but what do they actually mean?“.

Well, we’re going to tell you what they mean. So, by the end of this page, you’ll have a better idea of what each CPU is best suited to, and which one is the right choice for your particular use case. We’ll start, as ever, with the specs.

The differences between the Ryzen 9 9900X and Ryzen 9 7900X are relatively minor, when it comes to specs. Identical number of cores, threads, and the same Turbo Clock speed, too. Additionally, the L2-Cache and L3-Cache remain the same. This means that if you were to upgrade from the 7900X to the 9900X, you should not expect a particularly noticeable increase in performance especially when it comes to gaming. CPU-intensive games could see a modest improvement at regular settings as the base clock is 200MHz higher.

However, there is one spec that pops out as substantial, and that’s the TDP or Thermal Design Power. Given the almost identical specs, a 50W reduction in TDP is significant. In terms of actual end-user benefit, this means two things: The first is that your CPU cooling solution, be it a tower cooler such as the CORSAIR A115, an AIO like our H150 series, or an elaborate custom cooling loop won’t have to work so hard, so your PC will be quieter. The second is the knock-on effect where you won’t be using as much energy, while still getting almost identical levels of performance. Good for the environment, and your wallet. Speaking of cooling, neither of these CPUs come with a cooler, so you’ll need to grab one from the CORSAIR webstore.

Time to talking money:

• Ryzen 9 9900X Price: $449.99/£449.99
• Ryzen 9 7900X Price: $339.99/£349.99

The Ryzen 9 7900X has had almost two years to depreciate at the time of writing. This has resulted in a sizable price difference between it and its slightly improved younger brother. This means that the value proposition might be hard to swallow for some. That being said, the Ryzen 9 9900X’s significantly lower TDP and compatibility with the upcoming X870 and X870E motherboards might make it a more attractive prospect for those looking to future-proof.

If you’re looking purely at the price-to-performance ratio, then the Ryzen 9 7900X is the best option right now. It’s heavily discounted and will only continue to get cheaper. Additionally, from a raw specs viewpoint, it’s basically identical to the Ryzen 9 9900X.

However, unlike the Ryzen 9 7900X, the Ryzen 9 9900X is compatible with the soon-to-be-released X870 and X870E platforms, so it will hold up better going forward. You’ll just have to pay more for that privilege.