Conclusion
The AMD Ryzen 9 7900 was introduced on January 10th, 2023, with an original introductory MSRP of $429 this new “Non-X” variant from AMD ushered in a new series of 65W processors. These new 65W CPUs filled in the AMD Ryzen 7000 series CPU line based on the Zen 4 architecture and AM5 platform supporting PCIe 5.0 and DDR5.
The Ryzen 9 7900 has the same core count as the Ryzen 9 7900X, but a lower 65W TDP and thus a lower clock speed. The Ryzen 9 7900 is a 12-core/24-thread CPU that has a base clock of 3.7GHz and a boost clock of up to 5.4GHz, but only under lightly threaded usage. It has the same cache as the Ryzen 9 7900X. On the plus side, the Ryzen 9 7900 comes with the AMD Wraith Prism air cooler in the box, so you also save money not having to purchase a cooler of your own. Be sure to check current online prices, to see what they are at the current time, they can change over time.
CPU Performance of Ryzen 9 7900 vs Ryzen 9 7900X
In today’s CPU performance comparison review, we put the Ryzen 9 7900 versus the Ryzen 9 7900X to see how they compare. We also enabled PBO on the Ryzen 9 7900 to see if boosting past the 65W TDP can regain some performance closer to the Ryzen 9 7900X.
Starting with synthetic system benchmarks, in PCMark 10 the Ryzen 9 7900 was just 5% slower than the Ryzen 9 7900X. The catch here is that this test is of lightly threaded, lighter workloads, not something that would maximize all cores at the same time. That is still important because it does replicate more closely what is done in office work. In Geekbench 6 and 3DMark’s CPU Profile test, we can drill this down a bit more by looking at multi-core and single-core performance. In Geekbench multi-core performance the Ryzen 9 7900 was 8% slower than the Ryzen 9 7900X, and in single-core performance, it was only 3% slower. 3DMark shows it best, with the multi-core performance of the Ryzen 9 7900 being 19% slower than the Ryzen 9 7900X. In single-core performance, it was only 3% behind.
Moving on to the rendering benchmarks, we see much of the same replicated here. In Cinbench multi-core the Ryzen 9 7900 is 18% slower, but in single-core it is only 3% behind. In Blender the Ryzen 9 7900 is between 15-18% slower than the 7900X. In HandBrake there is also a difference, there are several minutes difference in encoding time, and it can add up for long render times.
In all of these synthetic benchmarks, enabling PBO greatly helped performance in multi-core performance. We saw performance almost completely match the Ryzen 9 7900X, and if not, it came very close.
When it comes to games, it is going to depend on the game, video card, and resolution. You will mostly see larger differences at 1080p, and you will need a fast GPU to see the differences. If you are GPU bound, then there really won’t be a difference between the Ryzen 9 7900X and Ryzen 9 7900 for gaming. However, if you have a fast GPU like the RTX 4090, then you could see performance differences in the single-digit percentages. At most, the largest difference was saw was 6% performance between the Ryzen 9 7900 and Ryzen 9 7900X. On average, differences were only 1-4%. We also enabled PBO, and that clawed back a little performance, but it ultimately did not equal the 7900X.
Final Points
In our testing, we found that the Ryzen 9 7900 has a larger difference in performance versus the Ryzen 9 7900X when it comes to multi-core, multi-threading performance. When you utilize all the cores, there can exist a 20% performance difference between the CPUs, with the advantage of the Ryzen 9 7900X. If you are doing things like rendering, or video encoding or editing, then the Ryzen 9 7900X has the advantage that may be worth the money. However, if you are doing lightly threaded workloads, or more single-core, single-threaded workloads, then there isn’t a large difference between the CPUs. The Ryzen 9 7900 can perform within 3-4% of the Ryzen 9 7900X in these types of workloads. The cost savings may be worth it then to go with the Ryzen 9 7900.
When it comes to gaming performance it depends on your goals and video card. If you aim for the absolute highest framerates and need to hit high framerates for very high refresh rate monitors, then the Ryzen 9 7900X will give you that edge versus the Ryzen 9 7900. However, if you game at high resolutions, like 1440p or 4K, and are GPU bound, then the performance with the Ryzen 9 7900 is practically the same as the Ryzen 9 7900X for gaming. The cost savings you save with the Ryzen 9 7900 could go toward buying a better video card, and that’s probably the best bet if you are serious about gaming.
Overall, AMD succeeded in making a very efficient 65W TDP CPU. We found the power utilization to be very appealing with the Ryzen 9 7900, plus it runs at a very cool temperature. This is the perfect CPU if you are concerned about power usage, or if you are building in a small form factor PC. We also found that PBO can pretty much claw back most of the performance of the Ryzen 9 7900X, if you wish to exceed that 65W TDP. It at least gives you options, if you really needed to push it further. The Ryzen 9 7900 is a good option to give you 12-cores/24-threads of CPU performance at a good price, with lower power, and it includes a cooler in the box to boot. It’s a great overall package.