The performance benefits provided by the FX-9370 and FX-9590 are as good as expected but we are more interested in learning about their power consumption. On one hand, AMD has increased their TDP up to 220 watts but, on the other hand, it is hard to believe that a 17.5% increase in clock rate could provoke a 75% increase in power consumption and heat dissipation. The FX-9370 and FX-9590 have the same design as other Vishera-based products but work at higher voltage, so their power requirements must be higher, but we haven’t yet seen a CPU consuming up to 220 watts!
Of course, we tested the power requirements of our off-the-shelf samples of the FX-9370 and FX-9590 processors. The graphs below (unless specified otherwise) show the full power draw of the computer (without the monitor) from the wall socket. It is the total power consumption of all system components. The PSU's efficiency is taken into account but our Corsair AX760i is a highly efficient 80 PLUS Platinum product, so its effect on the result is very small. The CPUs are loaded by running the 64-bit version of LinX 0.6.5 utility with support for AVX, AVX2 and FMA instructions. Moreover, we enable Turbo technology and all power-saving technologies to correctly measure the computer's power draw in idle mode: Intel’s C1E, C6, Enhanced Intel SpeedStep and AMD’s Cool’n’Quiet.
We’ve got a familiar picture in the idle mode. Every modern processor features advanced power-saving technologies which help it effectively shut down in this situation. So the diagram is indicative of the platforms’ rather than the CPUs’ power requirements, and the LGA1150 platform is obviously more economical. The Socket AM3+ platform uses a two-piece chipset with much higher power consumption than the senior LGA1150 chipset Z87. That’s why the Haswell-based configurations need less power at very low loads.
When it comes to single-threaded loads, the top-end Vishera-based CPUs consume 70% more power than their Haswell-based opponents. As you can see, their power requirements are much higher compared to the FX-8350. It is because the voltage of the FX-9370 and FX-9590 is additionally increased in Turbo mode, occasionally reaching up to 1.5 volts.
The FX-9370 and FX-9590 really need 100 to 120 watts more power than the FX-8350 at full load. As a result, the overall power draw of a configuration with a top-end Vishera-based CPU may be twice that of a Haswell-based configuration that would deliver the same performance and cost the same money. In other words, the FX-9370 and FX-9590 are far from economical and may have a very negative effect on the user’s electricity bills.
We can also note that the configurations with AMD’s top-end CPUs need even more power than Intel’s LGA2011 configurations with senior six-core CPUs, which means that the FX-9370 and FX-9590 are very poor in terms of per-watt performance.