Laptops with Solid State Drives: Pros and Cons

With Apple’s sexy MacBook Air thrusting them into the limelight, laptops with built-in solid state drives (SSDs) are suddenly all the rage. Now they are also available from a variety of Windows OEMs including Lenovo, Toshiba and Dell. While the drives can offer higher performance than conventional rotating storage, they also add about $500- $800 to the base purchase price of laptops, and can be almost ten times as expensive as a standard hard disk.

Groups of SSDs are also being found in higher-end storage area network arrays for bigger storage needs too. Examples include Texas Memory Systems’ RamSan, Solid Data Systems’ StorageSpire, and Violin Memory’s 1010 appliances – which can hold at least a terabyte of data.

What are some of the things to consider in buying an SSD-capable laptop, and are there situations where you would better off with the conventional hard disk-equipped models?

First, let’s look at the typical configurations that are currently available. Many manufacturers offer SSDs with (at the bottom end) 32 GB of storage, which can be limiting if you need the space for videos, photographs, or a large email archive. Toshiba sells its laptop with 128 GB SSD, the same price that it earlier offered a model with half that capacity. Dell sells a laptop that starts around $1,500, while the others have configurations that are at least $2,500. Dell also has the widest selection of SSD-capable models: two lines (Latitude and Precision Workstation) and multiple models (at least at this writing) of each.

What about the need for speed? Are the SSDs faster than conventional disks?

For the most part, yes. Dell claims that its SSD can improve Latitude D430 performance up to 23 percent and can reduce boot time by up to 34 percent. Other analysts have seen similar results, because you don’t have to wait for the drive to spin up or for the rotors to seek the specific place on the platter to read the data.

Apparent drive speed is made up of several factors: access time, or the time it takes for the disk to locate the data stored on the surface, and transfer rates, or how fast the information can move through the various electronics and bus connectors to the central processing unit of the PC itself.

The speed benefits really are noticeable for the bigger disk arrays, where transaction processing keeps up with nearly continuous storage requests.
One user, the electronics cataloger IC Source, replaced their conventional disk drive arrays with the SSD-based RamSan for their database application.

“For us that was a major breakthrough in speed,” said Peter Moran, President of IC Source. “Let’s say you update inventory at 8:00 AM. With the old RAID array you would be lucky to have it in the database by 1:00 PM. Now with the RamSan, you can expect to see it online within the hour. In some cases the inventory is updated in just seconds.”

But speed isn’t the only criterion. What about how much power is used by the SSD, and what it will do to the overall battery life of the laptop?

Before you can make any definitive conclusions, you have to look at more than just the SSD itself. “You need to know what chips and technologies are being used inside the SSD along with what kind of data connection is being used between the SSD and the overall PC itself,” says Brian Beard, the Flash Marketing Manager at Samsung.

Beard talks about two factors that can swing SSD-based laptops to either save or consume more power. “First, you have to examine the disk controller used in the laptop,” he says. Thinner and older laptops – such as the MacBook Air and the older Dell 430 models — make use of a parallel ATA interface, which uses electronics that can consume more energy and degrade battery life. “The newer laptops use SATA-2 interfaces, which use half the power of the parallel ATA interfaces,” he says.

The second factor is whether a laptop can be designed around the SSD and optimized for its use, versus having an optional SSD component. “These laptops can be designed for tremendous power and battery life savings, and can use a slightly slower CPU but still get equivalent or better system performance, while saving on power and heat,” says Beard.

Tests by Tom’s Hardware have found that battery life and power can vary tremendously, depending on the particular SSD and the particular conventional hard drive model.

“The truth is that no general conclusion, such as ‘Flash SSDs are more efficient,’ can be drawn at this point for the majority of the Flash SSDs on the market,” according to Tom’s testers.

The article shows that the newer conventional hard drives, especially those for laptops such as the Hitachi Travelstar line, have several different power-saving states, making them very energy efficient. The tests at Tom’s compared several different SSDs and conventional drives, and found that some SSDs, such as from OCZ, provide five times better performance per watt of energy consumed than the conventional drives. Where the SSDs become more efficient is when they are in use more often, such as playing a DVD, or serving up a transaction database.

“Flash SSDs do not inherently contribute to increasing battery life and better efficiency comes with the appropriate Flash SSD used for a specific application. ‘Flash SSD’ is not a qualifier for efficiency or performance.”

Where SSDs do shine is in reliability, because they have no moving parts. They can be used in harsh environments, such as in hotter climates or places where PCs will be moved about frequently and subject to shocks and vibrations. Samsung claims that its drives have a factor of six times better failure rates, meaning that they will last longer and have lower support and replacement costs.

But any discussion about costs should take into account the overall cost of ownership and factor in support and other costs. IDC, in a report last year, estimates that SSDs can save each user about $176 a year from various elements, including support, power efficiency, and productivity improvements.

Samsung also has a total cost of ownership calculator on their Web site (samsungssd.com) so you can calculate your own savings, if you buy into the IDC analysis.

SSDs are here to stay, and the initial price differential will continue to close as the memory and electronics become cheaper. Certainly, they are worth a look. And, if you are going to contemplate buying them as a laptop standard, worth doing some additional testing to determine if the battery life will be a net gain under your own circumstances.

And for high-demand computing situations such as transaction servers, they might make a big difference, as the IC Source folks found out.