Power Consumption and Temperature
To measure the power consumption of our HDDs we used a special testbed capable of monitoring electric currents on the 5 and 12V power rails. We measure average consumption in different modes: idle, random reading/writing and sequential reading/writing. The HDDs run IOMeter in this test.
The RE4-GP series was expected to be the most voracious in this test but we must admit that up to 8 watts per one HDD isn’t very much. As for the Green and the Red, the former has the lowest idle power draw of less than 2 watts, but when there is some kind of disk load, the Red is more economical. Power adapters of modern NASes will surely be able to deliver the required amount of juice. Let’s just check out the startup currents.
There’s no reason to worry here, considering that the HDDs usually start up one by one rather than all together.
The low power consumption has a positive effect on temperature. So, we checked out our HDDs using the NAS’s integrated monitoring system while running Intel NASPT on RAID5 arrays built out of four HDDs. The ambient temperature was about 22°C. We must admit that the results cannot be compared directly because the NAS has an active cooling system with an automatically regulated fan. We couldn’t monitor the fan’s rotation speed.
Anyway, we shouldn’t worry about temperature as it only peaked to 36°C. The WD Red series drives are somewhat colder than their cousins on average. This may be the reason why the system temperature was higher: the NAS’s fan worked at a reduced speed when we installed the Red drives.