Power Consumption
As you can see, there's very little difference between read and writes in terms of power consumption. What matters more is the amount of data transferred through the card and drives.
Our idle testing confirms that the installed SSDs can reach their lowest power ASPM sleep state when the BIOS settings are enabled (they are default off) and Windows Link State Power Management is set to "Maximum power savings." Even the empty card shows good power improvements with ASPM, which means that the Broadcom controller chip is able to transition into a low-power sleep state, too.