Posted by: Olly | February 26, 2007

Spinning down my disks

Good morning fellow workers of the world.

It’s been a while since my last post (I can tell you’re devastated). I’ve been penning a number of new articles, none of which have left the draft tick box behind, partly due to an abundance of work, small babies, stomach bugs, and colds. During last weekends bout of vomiting, I thought I needed to take my mind off things, so I whipped out my credit card and ordered a new 160GB disk for my Macbook Pro.

My old 100GB 7200rpm disk was filling up fast with virtual machines and retro gaming, so the extra space was much needed. However, the only 160GBs around today are 5400rpm, and I was somewhat worried about the spin speed difference. When I got my Macbook Pro, I made the effort to get the most, the fastest, the best I could get, as getting work to shell out for one is usually a one time deal :) Now, there’s a lot of talk from both techies and newbies alike to say that 5400 rpm disks are noticeably slower than 7200 rpm disks.

For those of you that don’t know the importance of the spin rate of hard disks (RPM=Revolutions per minute) heres a very (very) simplistic overview:

Inside your hard drive are lots of circular layers of silicon called platters. These are where the data is stored. The data is read from these (and written to these) by read/write heads which hover at miniscule distances from the surface of the platters and are fixed in position, with the platters rotating beneath them. Whenever you request a piece of data (be it a document, or an email or whatever), the computer looks up the position of the data on the disk, and tells the read head where to read the data from. The platters spin round until the read head is above the correct location and then they start the process of retrieving your data.
Now, the basic premise of the importance of spin speed (and it is basic, as other factors can, and do, come in to play) is that the faster the platter can spin round and present the read head with the data, the quicker the data can get fed to your operating system (Windows etc). Given that doing anything in a modern operating system involves saving some piece of data (be it a small cookie in a browser just for a refresh or changing the ‘last accessed’ date on a folder you just looked at) even the slightest speed improvement can accumulate in to a visible speed increase.

Most people, when asked, will say “get the fastest disk you can”. It’s possible to find hardware benchmarking sites that will happily show that there is very little real word increase in a 7200rpm disk over a 5400rpm disk, but these are typically ignored.

Having swapped disks, and copied my data back, I sat and fiddled around. Now, I didn’t think I was writing this before I upgraded my disk, so I didn’t make any proper timings of things. I don’t really think that speed performance is all down to numbers-on-paper, it’s far more about the users perceived pleasure of the results – which is good as that’s all I have :).

Now, booting OS X does seem marginally slower, by a few seconds. However, that’s about the only noticeable issue. In my day to day usage of Entourage (aka Outlook for the mac), Word, Safari, Camino, Adium, MSN, Transmission, iPhoto etc etc, I see, and indeed feel, absolutely no decrease in speed. Indeed, there have been positives. The machine as a whole runs far cooler than it did. Users of Macbook Pros with the 7200rpm disks will confirm that the case behind the function keys can get very, very, hot. Now, it’s just a warm tepid. It’s also quieter, not that Macbook Pro’s are every really loud, but the soft noise of the fan is softer than it was. Also, today my battery has lasted longer than it. Most days I get in at 8:30am or so, and by 11:30am I’m in the red on the battery meter. Today, the first day after the upgrade, my work load is the same (most days here are the same), and yet the battery lasted until about 12:15am or so.

Clearly, this isn’t a scientific test, but for those you ummming and arrrring about whether to upgrade the size of your disk at the cost of speed, then do it. Don’t worry at all. There are areas that will notice a difference, Aperture users, Photoshop experts etc, but then it’s likely that they will be using larger, faster, external storage if they are serious about it.



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