Slowly but surely, we’re spinning up multiple Tom’s Hardware labs with Cybenetics’ Powenetics hardware/software solution for accurately measuring power consumption.
Powenetics, In Depth
For a closer look at our U.S. lab’s power consumption measurement platform, check out Powenetics: A Better Way To Measure Power Draw for CPUs, GPUs & Storage.
In brief, Powenetics utilizes Tinkerforge Master Bricks, to which Voltage/Current bricklets are attached. The bricklets are installed between the load and power supply, and they monitor consumption through each of the modified PSU’s auxiliary power connectors and through the PCIe slot by way of a PCIe riser. Custom software logs the readings, allowing us to dial in a sampling rate, pull that data into Excel, and very accurately chart everything from average power across a benchmark run to instantaneous spikes.
The software is set up to log the power consumption of graphics cards, storage devices, and CPUs. However, we’re only using the bricklets relevant to graphics card testing. Gigabyte's Aorus GeForce RTX 2080 Ti Xtreme 11G gets all of its power from the PCIe slot and a pair of eight-pin PCIe connectors. Should higher-end 2080 Ti boards need three auxiliary power connectors, we can support them, too.
An average power reading of just under 18W is a little higher than what we measured from GeForce RTX 2080 Ti FE. Then again, the Aorus GeForce RTX 2080 Ti Xtreme 11G does have an extra fan, plus a bunch of lighting that the FE board lacks.
It’s also worth noting that Gigabyte offers semi-passive functionality, which cuts power consumption slightly. But we prefer a bit of active cooling, even at idle load levels, so we test with the fans spinning.
Running the Metro: Last Light benchmark at 2560 x 1440 with SSAA enabled pushes GeForce RTX 2080 Ti to the max, yielding an average power consumption measurement of 302W. Most of that power is delivered evenly through both eight-pin auxiliary connectors.
We pulled most of the lower-end cards out of our comparison chart since they use quite a bit less power than the GeForce RTX 2080 Ti Xtreme 11G. However, AMD’s reference Radeon RX Vega 64 remains. Although it’s much slower through our benchmark suite, we can see that AMD’s flagship tries to maintain a similar power target.
Recording current through three runs of the Metro: Last Light benchmark gives us a line chart that resembles power consumption, naturally. Still, breaking the results down this way tells us that the PCIe slot hovers around 4A—well under its 5.5A ceiling.
Power consumption under FurMark isn’t much higher than our gaming workload. There is a slightly higher peak reading, and one of the eight-pin connectors shoulders more of the task than before. Still, an average of 303W shows that Gigabyte has its Aorus GeForce RTX 2080 Ti Xtreme 11G capped. Once that power ceiling is hit, voltage and frequency are scaled back.
Maximum utilization yields a nice, even line chart as we track ~10 minutes under FurMark.
Tracking power consumption over time in FurMark doesn’t look much different from what we saw under Metro: Last Light. The Aorus GeForce RTX 2080 Ti Xtreme 11G holds steady around 300W. AMD’s Radeon RX Vega 64 tries to maintain the same power level, but has to switch between throttle states after a few minutes. Even a GeForce GTX 1080 Founders Edition starts acting up after a while.
Current draw over the PCIe x16 slot is slightly higher than 4A, and well under the 5.5A ceiling defined by the PCI-SIG.
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