When is a 5400RPM hard drive faster than a 7200RPM one?

I take my laptop pretty seriously since I use it as my primary computer both at work and home. I'm picky about the performance, weight, screen and durability. It's the same for most of us at Guru Labs. A major line of work for us is lugging our laptops around the world delivering Linux training. The ThinkPad T series is a common sight around the office.

For years laptop hard drives ran at 4200RPM and were a major bottleneck in mobile performance. Fortunately 5400 and 7200RPM drives brought "desktop like" performance to laptops. Two years ago when I bought my ThinkPad T42p I went for the largest 7200RPM drive available at the time, 60GB. I have really enjoyed the speed and vowed that I wouldn't get anything slower than 7200RPM in my laptop. The only problem is that I have been a bit cramped by the space and, even today, the largest 7200RPM 2.5" laptop hard drive is only modestly larger at 100GB.

Not too long ago the Seagate Momentus 5400.3 ST9160821A 160GB Hard Drive was released and took the crown as the new champion in 2.5" laptop capacity. When I saw that it was a 5400RPM hard drive I was a bit bummed -- however when I found out it was the first hard drive to ship with perpendicular recording technology I was intrigued.

Reviews were hard to come by, and the ones I read didn't have any comparisons against 7200RPM laptop hard drives. I took a chance and bought one with the strong hopes that the high areal density would translate into performance that could match my 7200RPM drive.

Here are what the initial performance numbers (average numbers reported from several hdparm -tT runs) look like:

For my original 60GB 7200RPM drive:
/dev/hda:
Timing cached reads: 2104 MB in 2.00 seconds = 1051.93 MB/sec
Timing buffered disk reads: 114 MB in 3.00 seconds = 37.95 MB/sec

For the new Seagate Momentus 160GB 5400RPM drive:
/dev/hda:
Timing cached reads: 2112 MB in 2.00 seconds = 1055.82 MB/sec
Timing buffered disk reads: 122 MB in 3.00 seconds = 40.61 MB/sec

As you can see it exceeded, not just matched, the performance I have been used too. Additional benefits of the drive are quieter operation and the 5400RPM uses less power to increases my battery life. I'm very pleased.

At the Guru Labs office you can get easily blinded by all the shiny geek toys and I'm afraid I've triggered another round of upgrades. :)