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Test: AMD Ryzen 9 7900X in Eco Mode – Zen 4 can be that efficient







Ex works, the Ryzen 7000 CPUs are a bit thirstier than their predecessors, Zen 4 only works efficiently with Eco Mode.

With the Ryzen 7000, AMD has launched its new processors based on the Zen 4 architecture. Compared to their predecessors, the Raphael CPUs score above all with significantly increased clock rates. For example, the Ryzen 9 7900X achieves a 750 MHz higher clock than its predecessor in our test on one core and 700 MHz more clock on all cores. However, AMD buys the increase in clock speed with a power consumption that is increased by the same percentage, which means that the efficiency is not necessarily intoxicating, especially when gaming. Activating “Eco Mode” shows what’s really in Zen 4 and how efficiently the CPUs can work with a simple adjustment.

What is Eco Mode anyway?

The Eco Mode is not an innovation introduced with Ryzen 7000, but was already available with Ryzen 3000 and Ryzen 5000. Depending on the mainboard, Eco Mode can be easily activated in the BIOS, otherwise you must first activate Precision Boost Overdrive (PBO) in the BIOS and then select a corresponding profile in the Ryzen Master tool. Activation changes three important parameters that affect the power consumption of the CPU: Package Power Tracking (PPT), Electrical Design Current (EDC) and Thermal Design Current (TDC). These values ​​indicate how high the current can be over a short period of time or permanently and how high the maximum permissible power consumption is. The following image gives an overview of the standard values ​​of the Ryzen 9 7900X and the two different Eco Modes.

Socket AM5 TDP groups

According to AMD, a Ryzen 9 7950X in Eco Mode with 65 watts should still be faster than an unlimited Ryzen 9 5950X. We ran the 12-core Ryzen 9 7900X in the 65-watt Eco Mode for our tests.

AMD Ryzen 5 7600X in review

Small increase in efficiency in gaming

Especially when it comes to gaming, the Ryzen 9 7900X didn’t necessarily convince us in terms of efficiency. Although the Raphael CPU delivers a good seven percent more performance in 1080p than the 5900X, it also requires 12 watts more, which corresponds to an increase of 13 percent. In terms of both power consumption and efficiency, the 7900X ranks in the lower midfield and not only works more inefficiently than its predecessor, but also than the competition.

By activating the Eco Mode, we limit the power consumption to a nominal 88 watts. In all our gaming benchmarks, the 7900X runs into the power limit, which means that we can still measure an average of 90 watts in the end. This corresponds to a reduction in power consumption of twelve watts or twelve percent. The measured FPS decreases by only 1.5 percent at the same time, a difference that is measurable but nobody will notice in practice.

Power consumption when gaming in 1080p

In terms of efficiency, the 7900X can at least move ahead of its predecessor, but it still lags behind its direct competition, namely the Core i9-12900K. And another CPU does fare significantly better, despite delivering the same gaming performance. We’re talking about the Ryzen 7 5800X3D, which is content with just 57 watts on average.

Efficiency when gaming in 1080p

Great increase in efficiency in the creative sector

When all cores are fully loaded, the 7900X draws up to 175 watts from the socket in our test. On average over ten applications, the power consumption is 141 watts. With Eco Mode, the maximum can be limited to around 90 watts and the average drops to 82 watts. Specifically, that is 59 watts less or 42 percent. However, the application performance drops by only eleven percent at the same time.

As a result, the 7900X is still almost 13 percent ahead of its predecessor on average and on a comparable level with the 5950X and the 12900K, although of course it depends on the specific application in detail. Nonetheless, these numbers are really impressive and show how efficient Zen 4 can be when clock speeds aren’t pushed to the limit. Accordingly, it makes perfect sense to either operate the 7900X in Eco Mode or to undervolt it manually.

AMD EXPO: What is it and what does it do?

Test system at a glance

CPU

AMD Ryzen 9 7900X

motherboard

ASUS ROG Crosshair X670E Hero

BIOS

0604

BIOS settings

EXPO profile 2, PBO disabled, Global C-States enabled, BAR support enabled

CPU cooler

ASUS ROG Ryūjin II 360

graphic card

AMD Radeon RX 6900 XT (2700MHz Chip, 1.08V, Fast Timings, 2150MHz VRAM, 115% TDP)

R.A.M.

2x 16GB G.Skill Trident Z5 @ 5200MHz CL36-36-36-76

System SSD

Western Digital WD_Black SN750 1TB

Gaming SSD

SanDisk SSD Plus 1TB

power adapter

be quiet! Straight Power 11 Platinum 1000W





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