Power Consumption
Our exploration of power consumption begins with a look at the Strix RX 570 OC as it performs different tasks.
Similar to Radeon RX 580, AMD introduced an intermediate memory clock state so that the GDDR5 doesn't have to run at full speed with multiple monitors attached or while playing back video content. So long as your displays are set to the same resolution, this approach works just as well for Radeon RX 570.
When it comes to gaming, though, the card breaks out of its shell. A 30 MHz-faster GPU and a higher memory clock rate result in an additional 13W of power consumption. Our stress test looks even worse, maxing out the 200W power limit. These numbers show that Asus tries to do a better job stabilizing its boost frequency compared to last generation's version by increasing the card's power limit.
The average voltage measured during our extended test is 1.15V. That's 0.15V more than Asus' Strix RX 470 OC, and now you know how the newer card's higher frequency is hit and kept stable.
In the end, the older Strix RX 470 OC's 1270 MHz ceiling was more of a fantasy. Asus' RX 570 version makes higher frequencies an achievable reality.
A Closer Look
Our gaming and stress test power consumption curves are quite different. Even though the gaming measurements peak as high as 225W, average power consumption in this workload is relatively low.
The stress test registers significantly higher power use due to a more consistent load, which pushes the Strix RX 570 OC to its 200W limit.
Balancing Power Consumption
Our discussion comes back to the voltage regulator's three phases, and how that configuration relates to the current on each rail.
The motherboard slot experiences peaks of up to 6A, which exceed the PCI-SIG’s specifications by 0.5A. At 5A, though, our calculated average ducks in below the consortium's 5.5A ceiling. Six real power phases would have allowed for more control over the distribution, making it possible to avoid this imbalance.
Our measurements rise during the stress test. An average of 5.6A now exceeds the PCI-SIG's 5.5A limit. Of course, as we know from AMD's reference Radeon RX 480 (and the subsequent tests we were compelled to run, proving our initial observations), that doesn't mean your motherboard will catch on fire. But it also doesn't bode well for overclocking, particularly on older platforms.
The following bar graph provides a general overview of the results:
When you don't have the key, a crowbar will do. Rather than following up Radeon RX 470 with finesse, the company figured out a way to coax higher clock rates out of Ellesmere by increasing the GPU's voltage.
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