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2.5" Serial ATA hard drive round-up


Big performance, little drives
— 12:00 AM on February 14, 2006

MOBILE HARD DRIVES have never been particularly fast, so the fact that hard drives are typically the slowest components in the average PC counts for even more in the laptop world. There was a time when 4,200 RPM was the norm for 2.5" notebook drives, and even today, 4,200-RPM drives are fairly common. Fortunately, those seeking better mobile I/O performance have an increasing number of options. Numerous manufacturers offer faster drives with 5,400RPM and even 7,200RPM spindle speeds, the latest of which also boast speedy Serial ATA interfaces and support for Native Command Queuing.

Serial ATA and NCQ are relatively new to the laptop world, and 7,200-RPM spindle speeds and high-capacity platters are still pretty cutting-edge for the 2.5" mobile form factor. The question, of course, is how well the latest Serial ATA notebook drives have integrated these new features and capabilities. It's also worth asking whether there's really a big performance gap between 5,400- and 7,200-RPM notebook drives. To find the answers, we've assembled the latest 5,400- and 7,200-RPM Serial ATA notebook drives from Hitachi and Seagate and run them through the wringer. Read on for the surprising results.


A two-pair of mobile Serial ATA drives

2.5"?
The size and weight of traditional 3.5" desktop hard drives are obviously a little much for mobile applications, so laptop drives have their own 2.5" form factor. 2.5" actually refers to the width of a mobile drive's platter; In reality, 2.5" drives are typically 2.75" wide, 0.37" tall, and 3.96" long. That's tiny when compared with 3.5" desktop drives, which typically measure 4" wide, 1.03" tall, and 5.79" long. Mobile drives are nearly six times smaller than their desktop counterparts by volume, and looking at the drives side by side, it's easy to see the disparity.


A 2.5" Serial ATA drive dwarfed by its 3.5" counterpart

These smaller dimensions also allow 2.5" drives to be much lighter than desktop drives, which is an important consideration for mobile applications. Typical desktop drives weigh in at over half a kilogram, but the mobile drives we'll be looking at today are around 115g—roughly one fifth the weight. Lower weight helps mobile 2.5" drives sip less power, too, saving on all-important battery life. Perhaps most importantly, though, the 2.5" form factor's smaller platters are more resistant to physical shock. That's especially important for those of us who tend to toss laptops around with not nearly enough regard for the spinning mechanics inside.


Look familiar?

Despite their diminutive form factors, 2.5" Serial ATA hard drives actually use the same connectors as their desktop counterparts. These drives plug into standard SATA data and power cables, making them particularly intriguing options for small form factor systems. If enthusiasts are going to press mobile Pentium M and Turion 64 processors into action in toaster-sized boxes, they might as well bring along mobile hard drives to match.

Unfortunately, the connector compatibility enjoyed by 2.5" SATA hard drives doesn't extend to mobile ATA drives. Those drives require pin and power adapters to work with desktop ATA systems, which isn't quite as convenient.