The Quarch Chronicles

A speed chart is the part of an SSD review people read first, and it tells the least about living with the drive. Battery life and the way a drive behaves when it has nothing to do sit in a different measurement.

I collect that measurement alongside performance in my reviews for Tom’s Hardware, and several drives looked very different once I did. Some of the faster ones, like the WD Blue SN570, gave back part of their lead in efficiency. Idle draw, which no throughput chart shows, also separated drives more than I expected, as the Intel Optane P5800X shows below.

Power is half the story

Throughput charts tell you how fast a drive can go. They say very little about what it costs to get there. That is why I capture power in my reviews, alongside performance.

I use a Quarch HD Programmable Power Module to measure a drive’s draw directly, then compare idle, average and peak power against the work the drive did. Idle draw deserves more attention than it gets, since some SSDs consume watts at idle, while better ones sip just milliwatts. In a laptop, that difference decides how long you can work away from the charger.

Efficiency is not the same as low power draw. My Kingston KC3000 review makes the argument: a drive that uses more power during a task can still come out ahead if it finishes sooner and drops back to idle.

This is the race-to-sleep idea, and performance per watt is how I score it. I think the best controller is the one that knows when to rest.

What the numbers showed

A few examples from my reviews. The WD Blue SN570 was faster than the SN550, but it drew roughly half a watt more on average. That higher draw and weak file transfer performance gave it a relatively low efficiency score, even though its idle draw dropped by roughly 100mW. The Kingston KC3000 beat several other Gen4 drives on efficiency, though the WD Black SN850 and Samsung 980 Pro were both more efficient. The Intel Optane P5800X idled at roughly 3.3W and drew over 15W under load.

In my laptop upgrade test, a Dell Inspiron 15 5502 running MobileMark 2018, the WD Black SN850 ran for over 8.5 hours on a single charge and the Samsung 980 Pro for nearly 9.5, while the Phison E18 drives I tested ended the run hours earlier.

I describe how I run these captures on a validation bench in How I Made SSD Validation Repeatable. Flash Foundations, Part 5 covers what a power trace can reveal about a controller. Both go further than this page does. Start with whichever matches what you want to measure.