The SSD Power Consumption Hoax

More Issues with Ultra-Compact Form Factors Expected

In our comparison, we looked at the difference in battery runtime between four flash SSDs and a 7,200 RPM hard drive, all of which were 2.5” units. Differences between various 2.5” hard drives can be found in the number of platters used — single platter drives are slightly more efficient — and in rotation speed. Drives spinning at 5,400 RPM typically are more energy efficient, while delivering lower performance. In the case of flash SSDs, capacity doesn’t have much of an impact on power consumption: again, there are only idle and active states.

Be Careful With 1.8” Flash SSDs!

However, if we were to take this comparison into the 1.8” space, we can see that conventional hard drives require much less power due to 3,600, 4,200 and soon also 5,400 RPM spindles — typically no more than 2 W. In contrast, the power consumption of flash based SSDs would not change much, because the only significant difference would be the packaging.

According to the experience we had with an initial 1.8” flash SSD, we can say for sure that the power requirements aren’t lower than those of 2.5” flash SSDs. As a result, the flash based SSD will lose the power consumption battle against 1.8” mechanical hard drives.

Flash Performance Developments

While 1.8” flash SSDs will help to raise the performance levels of ultra portables to the same level of compact mainstream business notebooks, most developments can be followed in the 2.5” space.

Performance has improved quite a bit since we received the first flash SSD for review from Samsung. That drive reached a read throughput of 50 MB/s, while delivering less than 30 MB/s in write performance. Today, we are looking at Flash SSDs that deliver way beyond 130 MB/s in read throughput and almost 100 MB/s in writes. All of these drives are based on SLC Flash, and cost $1,000 and up, depending on capacity.

MLC Dominates, But Doesn’t Win

For now, SLC flash is the only option to reach these performance numbers, although MLC is the alternative to achieve higher capacities (due to cost issues), and to move flash based hard drives into the mainstream. All the big flash manufacturers such as Intel focus on MLC flash, because it is cheaper, though not quite as fast as SLC.