MacTexan Wallpaper o' th' Week

Sedona Starry Night

Help us, WE'RE BROKE:
Search MacTexan
MacTexan on Twitter

« iperf3: A Simple and Fast Tool For Network Troubleshooting | Main | Why Won't My Mac Go To Sleep? »

Swap the Hard Drive in a 2009 27" iMac with a SSD

Crucial M4 512 GB SSD ($399 at Amazon)As I've said many times before, I love my 27" iMac (11, 1). I bought it as soon as it was available in late 2009. I ordered it from Apple with the fastest Core i7 available (2.8 Ghz), 2 gigs of RAM and the standard 1TB hard drive. I simultaneously ordered a 16 GB memory kit from OWC and it was waiting when my new iMac arrived. I upgraded the RAM before I turned on the machine for the first time. Note: Never buy RAM upgrades from Apple unless you're buying a machine (MacBook Air or Retina MacBook Pro) with non user-replaceable memory. OWC is a terrific resource for RAM chips at half the cost Apple charges and swapping memory is a pretty simple thing. (For now, that is. I think the days of DIY Mac memory upgrades may be numbered.)

With its beautiful 27" display and i7 horsepower, this iMac quickly became my favorite computer of all time. The only complaint I've ever had was about the hard disk. It came from Apple with the standard 1 TB, 7200 RPM Seagate Barracuda. It is a fine hard disk and it has never given me any problems, but it is what it is, a hard disk. Before I continue, I need to give you a little background concerning my other Mac, a 2009 17" MacBook Pro. It's a 3.06 Ghz Core 2 Duo with 8 gigs of RAM. By all rights it shouldn't hold a candle to my iMac, but even though it has half the RAM and half the processor cores, it often felt quicker than the big boy. The reason: it has a 256 gig SSD. With less CPU, less RAM and less GPU than my iMac, my MBP booted much faster and apps launched faster still. I had to remedy this.

I've been window shopping for the last couple of years for an SSD to put into my iMac, but prices were just too steep. I wanted at least 500 GB of storage before going to all the trouble of ditching my original 1TB Barracuda. Two years ago, SSDs of that size were over $700. Too much. I could have gone with a $425 256 GB drive, but just didn't want to give up 3/4 TB of storage. Thanks to price erosion in the SSD market, the 500+ GB drives just tipped below the $400 mark. Time to strike.

I bought a Crucial M4 512 gig SSD and a Thermaltake 3.5 - 2.5" adaptor from Amazon for $428 a couple of days ago and began studying how to disassemble my precious 27" machine and replace the boot disk. As always, I found all the information I needed at Note: If you ever need to fix or upgrade a Mac, check with They have an extensive array of on-line Mac repair and upgrade procedures complete with high-res photos, videos and instructions even a novice can understand and follow. 

One thing I learned was that Apple uses the temperature sensor built into the factory hard disk to control the hard drive cooling fan. There is a separate cable to this sensor that plugs into the logic board. Unless you buy a replacement drive from Apple, disks don't come equipped with this sensor. Leaving this cable unplugged will cause the hard drive fan to run at max and sound like a vacuum cleaner. After bouncing around a few forums and help documents, I learned of three solutions to this problem. One is to buy an external sensor made for the optical drive and tape it to the side of the new disk as a replacement for the on-board sensor. The second is to create a jumper and short the pins on the sensor cable to fake-out the machine into thinking the drive was cool. The third was to install the $29 HDDFanControl app that tells your Mac to use the drive's S.M.A.R.T. sensor instead of the on-board one. I chose option three.

Apple's oddball temperature sensor.

This morning, with parts and tools in-hand, I shut down and unplugged my iMac, placed it on my bed and followed iFixIt's instructions. Forty minutes later, the machine was back on my desk, plugged in and ready to go.

What happened when I pushed the power button put a huge smile on my face that is reappearing now as I write about it. The familiar Apple startup chime sounded, then a couple of seconds later the Apple logo appeared. I looked for the progress "spinner" for a second, but then the desktop appeared instead! In another three or four seconds the machine was completely booted. I couldn't believe it, so I restarted. This time I used the stopwatch on my iPhone to see just how quick it was. 31 SECONDS from startup chime to fully running. Also, launching most apps happens so quickly their icon doesn't bounce in the dock! This iMac runs better now than when it was new. The HDDFanControl app works as advertized, keeping the drive temperature between 105º - 125º by controling the fan speed properly. My only regret was not doing this sooner.  Anybody need a 1TB iMac disk?

Reader Comments

There are no comments for this journal entry. To create a new comment, use the form below.

PostPost a New Comment

Enter your information below to add a new comment.

My response is on my own website »
Author Email (optional):
Author URL (optional):
Some HTML allowed: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <code> <em> <i> <strike> <strong>