AMD Ryzen 7 5800X Review: The Pricing Conundrum

Ryzen 7 5800X Power Consumption, Thermals

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Notably, AMD's decision to stick with the AM4 socket still constrains its maximum power consumption to 142W, which means that it could not increase power consumption for the new flagship models. However, Zen 3's IPC gains allow the Ryzen 5000 chips to stay within the same TDP thermal and electrical ranges as the Ryzen 3000 series CPUs while delivering more performance.  

As such, the 105W Ryzen 7 5800X must adhere to the same 142W PPT limit as its 105W predecessor. As you can see in the y-cruncher threaded benchmark results, the Ryzen 7 5800X consumes a peak of 112 watts at stock settings in this heavy AVX workload, which is much higher than the previous-gen Ryzen 7 3800XT. We also see more power consumption during the HandBrake and Blender runs, but the deltas aren't as pronounced in these heavily-threaded workloads.

The increased power consumption comes as a natural byproduct of AMD's revamped boosting algorithms that let the chip skirt the limits of its thermal envelope during stock operation, consuming more power to maximize performance potential. 

Naturally, more effectively consuming that extra thermal headroom results in higher performance. In tandem with Zen 3's higher IPC, this typically exposes higher efficiency, but we did catch an exception to the rule. Our measurements indicate that the Ryzen 7 3800XT is just as efficient as the 5900X in our HandBrake x264 tests, but the 5800X is more efficient in other types of workloads, like the AVX-heavy HandBrake x265 benchmark. Interestingly, the Ryzen 7 3800X beats the 5800X in terms of efficiency, but it also operates at a much lower overall clock rate of ~4.1 GHz during the test, while the 5800X runs at ~4.5 GHz. As a result, the 3800X lands further down the voltage/frequency curve, granting it an efficiency advantage in these specific workloads, but that results in reduced performance. Conceptually, think of this as akin to the 3800X being a 3800XT running in AMD's Eco Mode. As always, there are tradeoffs associated with design goals, and here it seems that AMD's decision to push the performance envelope results in slightly lower efficiency in a few rare workloads.  

Intel's chips are rather inefficient in comparison, which is a natural byproduct of using the older and less-dense 14nm node. Intel has also turned the dial up on the voltage/frequency curve to remain competitive, throwing efficiency out the window in exchange for higher performance. 

The net-net is that the Ryzen 7 5800X, like other Zen 3 processors, will draw far less power per unit of work than any of Intel's 14nm chips, which results in a cooler and quieter system.  

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Here we take a slightly different look at power consumption by calculating the cumulative amount of energy required to perform x264 and x265 HandBrake workloads and two Blender renders. We plot this 'task energy' value in Kilojoules on the left side of the chart.

These workloads are comprised of a fixed amount of work, so we can plot the task energy against the time required to finish the job (bottom axis), thus generating a handy power chart. Bear in mind that faster compute times and lower task energy requirements are ideal. 

This measure really separates the wheat from the chaff, and the best results fall to the lower left-hand corner of the chart. You'll notice the modern Ryzen chips all populate the desirable bottom portion of the chart, while Intel's power-hungry chips climb to the top of the chart. Check out the Ryzen 7 1800X to see how far AMD has come in the efficiency department in a relatively short period of time. 

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