You'd be right to call Samsung out on their complete-BS-for-marketing power consumption figures.
I bet Samsung give very different figures to OEMs looking to integrate Samsung SSDs in their products. The label on the drive itself shows it rated at 5V 1.5A (i.e. 7.5W). Presumably that number is just over the maximum possible instantaneous power consumption of the drive.
Samsung say their figures are "based on MobileMark 2007", but that benchmark wouldn't stress an SSD at all. I reckon Samsung's "active" power consumption figure is an average power consumption over some test run, where the drive would actually have been idle over 90% of the time. MobileMark 2007 is a completely unsuitable way to derive an active power consumption figure, unless you're wanting to mislead consumers. Any reasonable person would assume, unless it's clearly stated otherwise, that active power consumption means power when the drive is actually reading or writing data.
Your review's ~3.5W figure shows how misleading Samsung's marketing power figures are. 3.5W is over
fifty times Samsung's published active figure. I bet if you were to enable DIPM on your desktop system or test the drive in a laptop, the sustained write power would still be similar to your review 3.5W figure.
There's been
some criticism of MobileMark 2007 for giving overly-optimistic battery life figures. The same would apply to using it to calculate drive active power. None of the applications in the benchmark stress the disk much.
Here's a quote from a
MobileMark 2007 white paper:
Quote
The Productivity module is somewhat more complex. One cycle of this workload is
completed every two hours. There is a fixed amount of work that takes place within that
period of time, with the balance of the time taken by fixed-length and variable-length user
delays distributed throughout the workload to simulate user “away” or “think” time. The
variable-length pauses ensure that a faster system and a slower system will do the same
amount of work in a given amount of time. This two-hour cycle is repeated until the
battery is depleted.
So as well as using applications which don't do much disk I/O, the MobileMark 2007 Productivity test pauses/waits a lot of the time. That would further increase the proportion of idle time.
Edit: Don't get me wrong, based on the reviews I've read the 840 Pro does seems like a great drive. It's just that Samsung's ridiculous marketing power figures make them come across as a bunch of charlatans.
This post has been edited by Donuts: 01 October 2012 - 10:50 AM