Efficiency & Over/Underclocking Results
Choosing the right benchmark for these tests poses a big challenge. We have to limit ourselves to one representative metric because there are so many data points to generate. Even then, it takes two full days to complete this section. In the end, we ended up going with Metro: Last Light again. It provides a balanced challenge for Nvidia and AMD graphics cards, and continues to offer a good ratio between performance demands and power consumption. We did change the settings due to your feedback, though.
We’re testing three different resolutions: 1920x1080, 2460x1440, and 3840x2160. The game now runs at its High preset, rather than Very High. We picked these settings because the GeForce GTX 1060 with Turbo Boost 3.0 and Radeon RX 480 don’t hit their highest power consumption numbers unless they run at higher resolutions.
Power Consumption & Attained Clock Frequency
The Radeon RX 480’s results are included as a reference, even though we're writing about Nvidia's GeForce GTX 1060.
First, we established the minimum power consumption and maximum clock rate. Then, step by step, we ran tests between both extremes that provided us with suitable curves for our results. Power consumption is shown on the y-axis, while the GPU Boost frequency is on the x-axis.
The GeForce GTX 1060 starts in the 60W to 62W range at all three resolutions. This corresponds to a GPU Boost frequency of approximately 1500 MHz. If you increase the power target to 116 percent and manually set the fan to 100 percent duty cycle, then the clock rate jumps to somewhere between 2050 and 2100 MHz, just like it did when we tested the 1070 and 1080.
AMD’s Radeon RX 480 starts with a GPU frequency in the 850 to 900 MHz range. These numbers are achieved with our "power-saving mode" and a voltage limited to a maximum of 0.85V. It maxes out at 1300 MHz, which is just 50 MHz higher than the stock 1250 MHz, and doesn’t really provide a noticeable performance gain.
Gaming Performance & Power Consumption
The competing cards' power consumption is now on the x-axis, and frame rate replaces clock rate on the y-axis. Using the graph's horizontal lines as a reference, we come away with the realization that Nvidia’s GeForce GTX 1060 requires 61W to achieve 130 FPS at 1920x1080, whereas the AMD Radeon RX 480 needs 139W for the same frame rate in spite of its adjusted voltage. In order to average 90 FPS at 2560x1440, the GeForce GTX 1060 draws just under 62W, whereas the Radeon RX 480 comes in at 146W.
Our scene isn't the perfect benchmark we wish it was. However, we were asked to make our tests as close to real-world as possible, so that's what we're doing. There's just nothing out there that'd give AMD’s Radeon RX 480 enough of a performance boost to make a significant dent in its performance-to-power consumption ratio.
But it's important to remember that we're talking about efficiency and not absolute performance. So let's get back to our main subject: when we've compared the efficiency of Nvidia’s GeForce GTX 1070, 1080, and 980 Ti, we see that a lower power target can do wonders for consumption. Then again, this solution does have its drawbacks...
Double-Checking the Results: Frame Time Curves
Average frame rates only tell part of the story, since frame delivery might wind up inconsistent, leading to perceptible stuttering. At 1920x1080, the curves for Nvidia's GeForce GTX 1060 in our power-saving mode (light green) and AMD's Radeon RX 480 (light red) are almost exactly on top of each other. These curves confirm our subjective experience: AMD’s graphics card does provide a somewhat smoother picture.
Lowering the Radeon RX 480’s power consumption results in significantly worse frame times though, whereas the GeForce GTX 1060’s do improve a bit with overclocking. This means that those who want to save power and still game at 1920x1080 without perceptible drawbacks shouldn’t go below 90W.
The situation looks similar at 2560x1440. Nvidia's GeForce GTX 1060 in our power-saving mode and AMD's Radeon RX 480 lose some ground to the stock and overclocked GeForce GTX 1060, though.
At 3840x2160, the Radeon RX 480's frame rate and frame time take a huge hit. Overclocking the GeForce GTX 1060 does provide some tangible benefit, even if the only way to game at this resolution is to dial detail settings back to their absolute minimum. In all fairness, neither the GeForce GTX 1060 nor the Radeon RX 480 are meant to game at 4K, though.
The GeForce GTX 1060 might not have a lot of overclocking headroom, but you should be able to get extra speed from the card, which translates to higher frame rates. At the other end of the spectrum, you could also save some power. Less-than-ideal frame times aren't great, but a card that maxes out at 62W is interesting, if only for exhibition purposes. It's clear to see how Nvidia gets away with just three power phases for its GP106.
AMD’s Radeon RX 480 represents a valid alternative for gamers who don’t place as much of an emphasis on power consumption. You'll just have to contend with more waste heat. Then again, if you cut it close with the capacity of your PSU, you may want to play it safe with the GTX 1060. This is particularly true for pre-configured PCs with one six-pin connector for accommodating upgrades.
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