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AMD Radeon R9 285 Review: Tonga and GCN Update 3.0

On paper, the new Tonga-based R9 285 looks to be slightly slower than the R9 280 it is intended to replace, but there's more than meets the eye.

Gaming Power Consumption Results

Power Consumption: Gaming Loop

For the gaming lop measurements we firstwarm up the graphics card for 20 minutes until a stable GPU temperature of 64 degrees Celsius has been reached. At this point we proceed to measure the card’s power consumption again. Our gaming loop is relatively challenging for the GPU, so we’re confident that the average 176 W we measured is a good representation of today’s demanding game engines. less demanding titles should draw between 165 to 170 Watts depending on the particular title, of course.

Once again, lets focus on just one minute of the smoothed curve. This shows us that the way the load is distributed between the PCIe and the motherboard power connectors conforms to the applicable norms.

The control exercised at the motherboard slot is reassuring. There’s never a sustained load that exceeds the slot’s maximum 75 Watt rating.

Let’s take a look at how the 176 W of power consumption while gaming are split in the table.

MinimumMaximumAverage
PCIe 12V33 W209 W124 W
Motherboard 3.3V3 W7 W5 W
Motherboard 12V9 W93 W47 W
Graphics Card Total47 W290 W176 W 

List of All Individual Values per Supply Line

Again, we’ve put together all power consumption values for each supply line in a handy gallery.

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Voltages

The average voltage is exactly 12 V, just like it was at idle. However, the fluctuations are present and accounted for as well.

The Gigabyte R9 285 WindForce OC and its 176 W for gaming comes in almost 40 W lower than a moderately overclocked AMD Radeon R9 280 reference graphics card, which also provides slightly lower performance on average. When we referenced the Gigabyte R9 285 WindForce OC’s efficiency on the graphics cards in our 2014 VGA charts, it looks like it’s comparable to Nvidia’s older Kepler-based GeForce GTX 760. If winning the efficiency war was the goal, then it most certainly hasn’t been reached, but at least AMD was able to catch up. This probably won’t be enough to compete with Maxwell, though.