Power Consumption: Testing Eight Different Settings
Similar to AMD's Radeon RX Vega 64, the Vega 56 offers two BIOSes with corresponding power profiles that can be selected using a switch on the card. If you don't change the driver-based profiles, the primary BIOS imposes a 165W package limit, while the secondary BIOS drops that to 150W.
We ran our maximum gaming load benchmark, The Witcher 3 at 4K, for all six combinations. In addition, we switched the Radeon RX Vega 56 to AMD's secondary BIOS, underclocked it slightly, and lowered the power limit by 25%. Finally, we also overclocked the card using its primary BIOS and increased the power limit by 50%. In total, this gives us eight different configurations to compare.
Let's start with power consumption, then move on to efficiency, frequencies, temperature, and noise:
We used our highest overclock to established the maximum motherboard slot power consumption. The 1.7A we measured is just 27% of the PCI-SIG’s specified limit of 5.5A. AMD has come a long way from the days of its Radeon RX 480.
In the end, we could have saved ourselves the trouble of dealing with a second BIOS, which requires that you shut your system down and open its case every time you want to toggle one way or the other. Our measurements show the primary BIOS' Power Save mode is similar to the secondary BIOS' Balanced mode, after all. From there, lowering the power limit by ~10% using the primary BIOS would roughly equal Power Save mode using the secondary BIOS.
Ultimately, two more WattMan profiles could have replaced the BIOS switch entirely.
Primary BIOS Power Consumption Graphs
For each BIOS, we provide comparison curves showing the voltage control at work and the loads on the individual power connectors over time.
Secondary BIOS Power Consumption Graphs
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