by , 2:45 PM EDT, May 27th, 2008

One can spend a lot of extra money for a 2.5 GHz MacBook Pro instead of a 2.4 GHz model and not gain much performance. However, the choice of hard disk can make a world of difference, according to Alan Zelchick in his bMighty.com blog.

"I've been writing on this topic since last September, but have become more convince than ever that drive speed is a killer feature. Think about the areas where modern desktops get their performance boosts from. The ones that get talked about the most like processor speed, aren't the most important in the real world," Mr. Zelchick explained.

He went on to look at all the specifications and performance areas where one might suspect that a linear increase in the specification might result in a linear overall increase in the MacBook's performance: CPU speed, processor cache, RAM, and front side bus (FSB). It seldom works that way, but the one specification that can dramatically affect the speed of the system, however, is the disk rotation speed.

"The older MacBook Pro (2.2G Hz processor, 4 MB cache, 3 GB memory) had a 200 GB hard drive that spun at 4500 RPM," the author noted. "The new one (2.4 GHz processor, 3MB cache, 2 GB memory) also had a 200 GB drive, but it rotated at 7200 RPM. It blew the old notebook away on every aspect of working with it. [Emphasis added by TMO.]

His advice was to skimp a little on processor speed and pour all that extra money into the fastest hard disk Apple offers. That's the smaller capacity but faster 7,200 RPM drives on the Mac Book Pros. He even concluded that it's a pity faster drives aren't made available, but that might be due to heat dissipation issues.