Volume Number: 23 (2007)
Issue Number: 01
Column Tag: MacTech Labs

Laptop Hard Drive Speed

4200, 5400, 7200 RPMs ... does it really matter?

By Neil Ticktin

It used to be that pretty much the only choices you had on laptop hard drives were size. But nowadays, there are a number of size choices (with larger sizes going from 100 to now 200GB), a couple of interface choices (PATA vs. SATA), and a few speed choices (4200, 5400 and 7200 RPM). As most 2.5 inch drive purchasers will tell you, there's a trade off between speed and size. You can't get the largest drives in the fastest speed ... in fact, they are almost inversely proportional.

For most laptop drive purchasers, the question becomes "how important are RPMs?" and "will I notice a difference?" With those questions in mind, we set out to do some real world testing, and see what we could find out.

For the test, we used an older PowerBook G4 running at 1.67GHz. We used the G4 to make the differences more apparent, but in general use, we found the G4's results to hold proportional and consistent with all Mac laptops, including the Core Duo and Core 2 Duo machines. Some overview information on these Hitachi drives -- skip to the next section if you are just interested in the test results.

Figure 1. Hitachi Travelstar Drive

Travelstar 7K100 and Travelstar 5K100 are part of Hitachi's range of 2.5-inch hard drives. These drives are available with either the Parallel ("old-school") ATA (ATA-6), or Serial ATA interface. Native SATA implementation offers throughput at 1.5 Gbits/sec, and supports Native Command Queuing (NCQ), Hot Plug, Staggered Spin-up, Link Power Management, and other SATA extension features to meet the design requirements of single drive systems, as well as multiple drive architectures. (Yes, we realize that the 'hot-plug' feature is of little use for an internal laptop drive...) The optimized Femto-based actuator/suspension system of the Travelstar 7K100 and Travelstar 5K100 allows them to withstand 300 and 1,000 Gs of operating and non-operating shock, and to last for 600,000 load/unload cycles.

The Travelstar 7K100, a series of 7200 RPM 2.5-inch hard disk drives, is available in capacities of 60, 80, and 100 GB with 3, 4, and 4 data heads respectively and 2 data disks each. The maximum areal densities of 60, 80, and 100 GB hard drives are 66, 66, and 81 Gbits/sq. inch respectively. The sector size in 7K100 series of 2.5 inch hard drives is 512 bytes with 24 recording zones. Data buffers of the 7K100 series is 8 MB with latency average of 4.2 ms. Average seek time is 10 ms for a read cycle, and 11 ms for a write cycle. Track to track seek time is 1 and 1.2 ms for a read and write cycle, respectively. Full stroke seek time is 18ms for a read cycle, and 19 ms for a write cycle. The Travelstar 7K100 has a media transfer rate of up to 625 MB/sec, and power consumption of 0.85 W in low power idle mode. Power requirements of the 7K100 series are +5VDC (+-5 %) with power consumption of 5.5, 2.3, 2, 2, 1.1, 0.2, and 0.1 W in startup, seek, read, write, active idle, standby, and sleep modes respectively. The operating and non-operating temperature ranges of 7K100 series are 5 to 55 degrees C and minus 40 to 65 degrees C respectively. Dimensions of 7K100 series hard drive are 9.5 mm height x 70 mm width x 100 mm depth. Hard drives in the 7K100 series are 115 grams in weight.

The Travelstar 5K100 is a series of 5400 RPM 2.5-inch hard disk drives, available in capacities of 40 to 160 GB with 2, 3, 4, and 4 data heads and 1, 2, 2, and 2 data disks respectively. The maximum areal densities of 40, 60, 80, and 100 GB hard drives are 70, 70, 70, and 86 Gbits/sq. inch respectively. The sector size in 5K100 series of 2.5- inch hard drives is 512 bytes, with 16 recording zones. Data buffers of the 7K100 series are 8 MB with latency average of 5.5 ms. Typical average seek time is 12 ms. Travelstar 5K100 has a media transfer rate of up to 493 MB/sec, and power consumption of 0.60 W in low power idle mode. Power requirement of 5K100 series is +5VDC (+-5 %), with power consumption of 5, 2, 2, 0.85, 0.2, and 0.1 W in startup, read, write, active idle, standby, and sleep modes respectively. The operating and non-operating temperature ranges of 5K100 series are 5 to 55 degrees C and minus 40 to 65 degrees C respectively. Dimensions of 5K100 series hard drive are 9.5 mm height x 70 mm width x 100 mm depth. Hard drives in the 5K100 series are 95 and 102 grams in weight.

Both series of drives feature Enhanced ABLE (Enhanced Adaptive Battery Life Extender), a power-management technology that dynamically selects the appropriate mode to minimize power usage, and help preserve battery life, when the disk drive is idle. Both series of 2.5-inch hard drives come equipped with Enhanced Error Correction Code for ensuring data integrity, and Fluid Dynamic Bearing (FDB) motor for quiet operation. These hard drives also feature TrueTrack, which is a suite of advance servo technologies that enable hard drives to maintain true tracking accuracy of the heads despite disk shift from shock or vibration. The drives are also RoHS compliant. Typical suitable applications for Travelstar 7K100 and Travelstar 5K100 include, notebook and tablet PCs, gaming devices, compact desktop systems, graphics and CAD workstations, external storage solutions, and video editing and surveillance.

These drives range from about $50-60 up to $200-250, depending on the model and size. For more information visit: http://www.hitachigst.com

There were two classes of tests that we ran -- shorter and longer ones. The longer tests included the time it took for booting to start after powering up, boot time, fixing permissions, a complex search in Eudora email, import into FileMaker, and having Safari open up many windows. The shorter tests included a file copy, launching Dashboard, launching Eudora, Safari and Word. In short, all the tests were not based around specs, but around real world operations. The system was identical on both, as were the contents of the drives.

Numerically, there was a noticeable difference: the 7200 RPM drive was 25-40% faster. The charts give you more detailed information.

Figure 2. Longer Tests, 5400 vs. 7200 RPM

As a user, what's more important is how it feels. And, there was no doubt about it ... the 7200 RPM felt considerably snappier and more responsive than the 5400 RPM drive, and while not included in the test, the 4200 RPM drive would have shown an even bigger difference.

Figure 3. Shorter Tests, 5400 vs. 7200 RPM

There's no question in our testing that the faster drives are noticeably faster. So, the question for you as you choose your drive is, "what's your priority?" If size is more important than speed, then go with size, but remember that not every operation will be as fast as your machine could make it. If speed is more important, then definitely go for the 7200 RPM drives in the smaller sizes. 5400 RPM drives are really the contemporary bare minimum speed you should settle for.

Neil is the Publisher/Editor-in-Chief of MacTech Magazine. Neil has been in the Mac industry since 1985. When Neil writes a review, he likes to put solutions into a real-life scenario and then write about that experience from the user point of view. That said, Neil has a reputation around the office for pushing software to its limits and crashing software/finding bugs.