SSDs I Have Known

Myth 1: A Solid State Disk will boot faster than mechanical hard drive.
This is true but it’s partially smoke and mirrors as well. When SSDs first appeared, they were rather pathetic 8GB and 16GB devices. Not much fits in that size. Even at 32GB you’ll still be somewhat cramped if you have hardware drivers and applications.

In fact, that’s where SSDs got their initial reputation for fast boots. With no drivers or background software to load, most of what you had to wait through was your portable’s BIOS, which probably took about 20 seconds, and then maybe another 35 seconds or so for the operating system.

But when you get to 64GB or 80GB or 128GB –and you have some room to feel confident about carrying the additional software you need around with you—you start to add time to the boot process. Depending on just how much you’re loading, you’ll probably be waiting at least an extra 15 seconds. To be fair, a similarly stocked mechanical drive can carry on for an additional 20 – 30 seconds and that’s what you’re paying to avoid with an SSD.

Myth 2: A Solid State Disk will extend your battery life.
This has to be a no-brainer. There is no way that an electronic device would use as much power as a mechanical device. Just starting a mechanical hard drive up from a dead stop draws power on the ampere level rather than the more modest milliamp power draw that just idling the drive requires. And because you’re moving physical read/write heads back and forth across the mechanical drive’s platters, sending data through an electronic trace to a memory cell on an SSD is the all-around winner in overall low-power draw.

Here’s the but: Many pundits treat a hard drive as the only component that uses electrical power. Au contraire! It is, in fact, a minor component –overshadowed by the power draw of your screen, CPU, memory, and GPU. The brighter your screen, the more intense your calculations or your display rendering, the more acutely do those four components suck your battery dry. And if you have an optical drive, lets not forget all the spinning that does while you’re watching Twilight.

So while it might be a no-brainer, don’t overestimate the impact simply having an SSD will have on your power lifestyle. You really don’t use a hard drive that much in most applications. And if it is longer run-time without the need to plug in that you desire, be prepared to cut back in other areas as well –like screen brightness– and use the toughest power saving options you can set through the control panel.

Myth 3: Solid State Disks Are Simply Wicked Fast
Again, we’re faced with an incontrovertible truth. SSDs are fast. In fact, some are faster than others. Among the consumer level SSDs, Intel’s X25-M is probably one of the fastest. Enterprise versions of SSDs, those like Intel’s X25-e meant for servers where the power savings of one SSD times 100 or 1,000 drives used in a deployment are significant, are even faster.

That may change at some point during the next year, as several manufacturers are promising speed-ups for their SSD products. SanDisk is among the boldest with a claim that it will crank up performance by 100x. Most of the emerging schemes rely on disk management firmware to increase an SSD’s overall operational efficiency as well as adding an extra cell to each memory location so there’s more information available at each cycle.

How fast are SSDs now? Well, we took SimpliSoftware’s HDTach and ran it on one of Intel’s 80GB X25-M drives and then on Western Digital’s 300GB Velociraptor. (With a SATA 3.0GBs interface and a 10,000rpm spindle speed, the Velociraptor defines speed among mechanical drives in its genre.) The verdict? The X25-M’s burst speed was 256.7MBytes/s and its Average Read towed the mark at 230.2MBytes/s. In contrast, the Velociraptor showed a 250.3MBytes/s Burst Speed and 105.6MBytes/s Average Read. That’s conclusive proof SSDs are faster, right? Maybe not.

Let’s journey outside of the typical commercial test and look at a simple file transfer operation. We took 4,661 directories and files in a 8.05GB group and transferred them to and from the two drives, using a third drive as the source and destination as needed. It took 264 seconds to write the data to the Velociraptor and just, um, 264 seconds to write the same data to the X25-M. That’s not faster in reality.

Reading the data from each drive saw the Velociraptor needing 242 seconds to complete the task while the X25-M required 221 seconds. All right, reading is faster with an SSD but it’s not really that much faster, just about 9 percent in our testing. More importantly, look at the difference between the read and write times for just the X25-M –43 seconds, nearly ¾ of a minute! As with all current SSDs, it’s heavily biased toward reading. (That’s one of the reasons boot speeds look so good.) Manufacturers are promising to reduce that disparity (by decreasing the write times, we hope) during 2009.