AMD Ryzen 9 7900 vs Ryzen 9 7900X CPU Review

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Power, Temperature, and Frequency of Ryzen 9 7900

On this page, we are going to investigate the AMD Ryzen 9 7900 power draw, temperature, and frequency. This is a stress test, which means we are pushing each CPU to its maximum potential in all-core load in Cinebench R23 multi-core test for 10 minutes.

Power

We use HWiNFO64 sensor data to record the results.  We report on the sensor data for “Package Power” in Wattage.

AMD Ryzen 9 7900 Power

The new AMD Ryzen 9 7900 has a TDP of 65W, while the Ryzen 9 7900X has a TDP of 170W. We can see these major TDP differences in the CPUs play out. AMD’s goal was to provide a lower TDP part in the “Non-X” CPUs, and they succeeded. The new Ryzen 9 7900 only consumed 90W package power, while the Ryzen 9 7900X consumes 201W. That is a 55% reduction in power usage!

Enabling PBO on the Ryzen 9 7900 allows the TDP to increase, and what we find is that it reaches much closer to the TDP of the Ryzen 9 7900X. That allows its performance to come very close to the performance of the Ryzen 9 7900X in our testing as was shown. This power shows what PBO can do here, it can increase the operating Wattage of the CPU to allow it to perform faster.

Temperature

We use HWiNFO64 sensor data to record the results.  We report on the sensor data for “Tcidle” in Celsius.

AMD Ryzen 9 7900 Temperature

We know that there is a big power difference between the CPUs, and we also see this represented in the temperatures. The Ryzen 9 7900X tops out at 92.8c, while the Ryzen 9 7900 is 38 degrees cooler and maxed out at just 54.3c. That is huge, this CPU would be perfect for a small form factor build, it just won’t require excessive cooling. Enabling PBO does increase temperature, as it increases power, but it still runs slightly cooler than the 7900X even with PBO enabled.

CPU Frequency

We use HWiNFO64 sensor data to record the results.  We report on the sensor data for frequency in MHz. The left screenshot is the Ryzen 9 7900 at default, and the right screenshot is the Ryzen 9 7900 with PBO enabled.

From this, we can see that the Ryzen 9 7900 at default operates at 4.175GHz-4.250GHz at default. Remember, the CPU boost frequency can boost up to 5.4GHz technically, but on all-core load, this is as high as it will go when all cores are being used. When we enable PBO (in the right screenshot) we now see that it can boost up to 5.075GHz-5.125GHz. This is quite a big boost in frequency, and this is why the Ryzen 9 7900 can almost reach the performance of the Ryzen 9 7900X when PBO is enabled. It also shows that on all-core load, at default TDP, it is quite far away from its maximum boost clock. It takes PBO to get it closer to that maximum. Again, this is on an all-core load, all cores pegged in Cinebench R23.

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REVIEW OVERVIEW

Performance
9
Efficiency (Perf per Watt)
10
Features
10
Value
9

SUMMARY

We reviewed the AMD Ryzen 9 7900 CPU and compared it directly versus the Ryzen 9 7900X to find out the performance differences in synthetic benchmarks and gaming performance. The Ryzen 9 7900 performed well but was quite under the 7900X in multi-core performance, but made up in single-thread or lightly threaded workloads where performance differences were small. The efficiency is excellent as a 65W CPU, and the features are top-notch. For the money, the CPU offers a lot of value and can be pushed higher with PBO, and a little tweaking. It offers a lot of possibility and options.
Brent Justicehttps://www.thefpsreview.com
Former managing editor of GPUs at HardOCP for 18 years, Brent Justice has been reviewing computer components since the late 90s, educated in the art and method of the computer hardware review, he brings experience, knowledge, and hands-on testing with a gamer-oriented and hardware enthusiast perspective. You can follow him on Twitter - @Brent_Justice You can sub to his YouTube channel - Justice Gaming https://www.youtube.com/c/JusticeGamingChannel You can check out his computer builds on KIT - @BrentJustice https://kit.co/BrentJustice

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We reviewed the AMD Ryzen 9 7900 CPU and compared it directly versus the Ryzen 9 7900X to find out the performance differences in synthetic benchmarks and gaming performance. The Ryzen 9 7900 performed well but was quite under the 7900X in multi-core performance, but made up in single-thread or lightly threaded workloads where performance differences were small. The efficiency is excellent as a 65W CPU, and the features are top-notch. For the money, the CPU offers a lot of value and can be pushed higher with PBO, and a little tweaking. It offers a lot of possibility and options.AMD Ryzen 9 7900 vs Ryzen 9 7900X CPU Review