Power Consumption and Noise
The PowerColor HD7870 PCS+ Myst Edition consumes a lot more power than the Pitcairn-based Radeon HD 7870. Occasionally, it even demonstrates higher power consumption than the Radeon HD 7950, though this is probably a result of its higher GPU voltage. If it seems like you've seen this play out before, think back to ATI's Radeon HD 5830.
Ah well. The table below has the most important power consumption-related numbers, along with noise levels that correspond to each workload.
|Load||Noise Level||Power Consumption|
|Idle||31.4 dB(A)||12 W|
(Radeon HD 7870 app. 12 W, Radeon HD 7950 app. 11 W)
| Blu-ray Playback||32.8 dB(A)||68 W|
(Radeon HD 7870 app. 45 W, Radeon HD 7950 app. 54 W)
|Gaming||37.8 dB(A)||175 W|
(Radeon HD 7870 app. 115 W, Radeon HD 7950 app. 145 W)
|Stress Test / GPGPU||40.3 dB(A)||200 W|
(Radeon HD 7870 app. 148 W, Radeon HD 7950 app. 180 W)
The temperature and fan speed curves fit with these numbers. PowerColor is pretty conservative with the HD7870 PCS+ Myst Edition’s fan control. It starts at only 25% duty cycle and revs up slowly as the temperature increases. Pushing the card hard does result in quite a bit of noise, but it remains bearable. Seemingly, PowerColor allowed higher temperatures to help keep acoustic output in check.
We achieved the temperatures in the chart above using an open test bed, but the card exceeds 75 degrees Celsius in a closed case (Corsair Obsidian 800D). This is just barely on the right side of acceptable, but certainly not a great result.