I recently decided to upgrade the internal hard drive in my iMac. What surprised me was how simple it really is to do, and how much of a performance benefit I gained.

Time Required: About 1 hour.
Tools needed: 1 new large and fast SATA hard drive, screw driver kit with Torx 6 and 8, 2 or 3 suction cups, can of compressed air, LCD cleaning cloth.

iMac ready to undergo surgery

I picked up my current 24" iMac September last year, it has suited me very well. But I've never been pleased that you can't add additional hard drives to the iMac like you can a Mac Pro, or most PC's. I have a couple of externals that I use for additional storage and for cloning with SuperDuper! Finally I decided that I'd be better served with a large drive in my iMac and a large external drive to clone it onto. Just a two drive system, no other externals for extra storage capacity - this is simple and easy and fits my lifestyle better.

Once I realized that a ReadyNAS NV+ really wasn't be best and easiest solution I began to look for information on how to go about upgrading the hard drive in a new iMac, I knew it wasn't a user accessible drive but figured somebody had figured it out. Sure enough - Tom Sawyer over on the MacRumor forums had been a pioneering fellow and posted a tutorial on how he did the deed. I read his write up twice and decided I could surely do this myself.

Tom has written a nice guide, but there were some things that I felt could have been elaborated on a bit more so I am writing up my experience in a guide.

• I'm sure you're wondering if you have what it takes to upgrade the drive in your own iMac. If you have ever put together a PC or maybe swapped out a motherboard in a PC, hell if you've ever watched McGyver I think you're qualified to take on this task successfully. Seriously, all you need are the right tools and some patience and care.

• Before beginning you'll need to get a new hard drive, I chose the Samsung F1 750GB drive which was $140 delivered from Newegg. I would have loved the extra space and outstanding performance of the Samsung F1 1TB drive, but it is almost double the price so I went with the 750GB instead. Hard Drives are like operating systems and religions, people firmly believe in the brands they like. I don't think you can go wrong with the Seagate drives, I'd stay away from the large Western Digital GP drives because they are only 5,400rpm despite being labeled as variable 5,400 to 7,200rpm. The new Samsung drives are getting mixed ratings at NewEgg, but most of the problems are because of some issue with these drives, Vista and nVidia drivers - nothing that affects us Mac users. I've used Samsung drives before and they've always been fast and dead silent, so my choice was easy.

• I read Tom Sawyers guide to doing the upgrade over at the MacRumor's Forums.

• Snagged a screw driver kit for the weekend from our IT guy at work, complete with Torx size 6 and 8, two most used items in the upgrade. You need suction cups to pop the protective cover off the iMac, instead of buying a set of them at Home Depot I opted to use the side window Sun Shade in my car which has two suction cups (happy to save a couple dollars in the process.) You'll definitely want to have a can of compressed air for cleaning out your iMac and getting all of the dust off of the LCD when you put it all back together.

My new 750GB Samsung F1, screwdriver/Torx kit, window shade (with suction cups), and Tom's tutorial

• I first removed the iMac from my office, and placed it lying facing up on my kitchen counter on top of a folded bath towel which was protect the iMac from case scratches.

• Next I attached the two suction cups to one side of the [plastic, not glass] cover on the front of the iMac. Here's one of the first mistakes I almost made. You really need three suction cups, two on one side at both ends, and one suction cup on the opposite end of the screen in the center. When I pulled the screen off with the two suction cups and started to pull it up higher, I heard a bad noise. It turns out that there are pins attached to the underside of the plastic cover, and unless you pull the screen relatively straight off, you can break these pins and or the entire plastic cover. I was working carefully so didn't damage my cover, but this was a close call. You can probably do it with just two suction cups if you pull the one end up only a couple inches then reach over and lift up the other side with your fingers. The red dots indicate where I would put the suction cups, lift with the side with two cups, when it pops up, lift with the third cup to fully remove.

• Be sure to take extra special care to not touch the LCD screen after removing the protective cover.

suction cups attached, ready to remove the cover.



protective screen now removed

• Next you need to use your Torx screw driver and remove all the screws surrounding the LCD screen from the aluminum front bezel. I put red dots on the picture above to show where the screws are that need to be removed to get the front bezel off.

• Remove the memory access panel now.

• Life the aluminum bezel from the top of the iMac, be careful to not lift very far, you need to disconnect the iSight.

iSight cable to disconnect

• After disconnecting the iSight cable, (be sure you removed the memory access panel, keep lifting the bezel from the top and wiggle it a little and it will fully come off the body of the imac. Where the bezel fits at the bottom of the iMac is just a tongue and groove type fit, you may have to push the bezel downward slightly at the bottom of the iMac after lifting the bezel at the top of the iMac. The bezel comes off very easy after disconnecting the iSight.

iMac with the bezel removed

• Next is to free the LCD from the iMac. First remove the 8 Torx screws holding it to the iMac (I show 6 of them with red dots in the picture above, there are 4 screws on either side of the screen.) When you begin to lift the LCD panel away from the computer, I found it best to lift it from the top by the iSight, pivoting at the bottom. When reinstalling the LCD panel, set the bottom in first then carefully put the top back down into the iMac.

• Side note - the main fan had a fair amount of dust in it, so I covered my LCD screen with a clean kitchen towel and cleaned the fan out with a can of compressed air. Look at the visible dust in the first picture, then how much cleaner it is after blowing it with air. Note - I also cleaned the other fan I noticed near the hard drive, I think there is a third fan also but I didn't notice it.

Dirty Fan



Clean fan

• There are two sets of wires that you need to disconnect from the iMac which prevent you from lifting the LCD away from the iMac. I didn't snap a picture of the fist set, but it is a set of 4 wires and they are just to the right of the main fan at the lower left of the imac. I've drawn a red line next to the wires in the picture just above.

LCD DVI connection.

• The next set of wires I think is the DVI connection, it is shown in the picture above, circled in red. Tom's guide talked about this being difficult to put back in upon reassembly but I found that it just snapped right in without any issue at all.

• Tom recommends removing the power connection to the LCD which requires removing a small circuit board, I think it's much easier and safer to leave it connected and work on the iMac with the LCD still connected to the power. If you have somebody to help they can hold the panel up for you, I did it myself, by putting the LCD just inside the lip of the iMac's back plastic case and tilting it up, then I rested the LCD panel on my head while I worked on the hard drive.

LCD panel tilted up



angled view

• The picture above shows where the hard drive is installed, my drive is out at this point but I outlined where it was in red.

• Before you remove the drive, you need to disconnect the thermal sensor, it is under a 1" foam square. Pull off the foam square, and remove the sensor attached to the wire from the plastic mount on the drive. I show a picture of the mount down below.

• To remove the hard drive you need to remove the two Torx screws on the top side of the drive, from the black plastic handle / mount.

• Carefully lift the drive up (where you just removed the two screws). There are two screw/pins mounted on the bottom side of the drive, pull it towards the top of the iMac to remove these pins from the mounts.

• Carefully remove the SATA and Power cables from the drive and lift the drive out of the belly of the iMac.

• Using a knife or screwdriver, remove the thermal sensor mount from the hard drive. I pushed it onto my new drive, and used a little Gorilla Glue on either end to ensure that it would stay put.

Thermal sensor mounting bracket.

• This item I either missed from Tom's guide, or he didn't list it, but on the other side of the hard drive is a small square of foam tape attached to the drive, it's about 3/8" square. I only noticed this after I'd put my iMac completely back together again, but you can certainly transfer it to your new drive now that you know about it.

• Now you being the reassembly of the iMac. Everything goes back together in exact reverse as the disassembly took place.

• One thing I messed up was when I sprayed my LCD panel to remove any dust, I tilted the can of compressed air too much and it sprayed liquid onto my LCD panel! I freaked out momentarily after seeing a reside remaining after it dried. Luckily an LCD cleaning cloth cleaned it up very easily. I would highly recommend you have one of these clothes handy, it's very likely that you will get a small smudge or two on the LCD during the drive upgrade - these clothes make quick work of them. I got my cloth with my LCD TV when I purchased it, but I think it's the same cloth used to clean optical glasses too.

I think I could do the job in about half the time the next time I do it, I was going slowly and cautiously, but it really wasn't as difficult of a job as I had been anticipating. In fact it was darned right easy to do.

Now that it's completed I'm really seeing the benefits. I've got a large internal drive with enough capacity to warehouse all of my data on a single drive. I only need 1 external firewire drive to Clone my main drive for safety (using SuperDuper!). I've decided to just go with a SuperDuper! clone and not use Time Machine.

SPEED, there's the great thing, my new hard drive is far faster than the stock Western Digital 320GB drive that it replaced. My Xbench score on my original drive was a respectable 72.91, the new Samsung F1 750GB measures 93.02, a 28% increase. This change (and going from 3GB to 4GB of RAM) increased my overall computers XBench rating from 151.17 to 164.95, a 9% overall increase. These are benchmarks you say, they don't mean anything! But I am seeing dramatic improvements in speed in real life usage as well. It now only takes about 6 seconds to launch Windows XP in fusion, about 3.5 seconds to close it. I'm seeing DOUBLE the transfer rates when doing the initial clone of my drive to my external FireWire drive. My iMac definitely is faster with disc activity than it was when stock.

I couldn't be more pleased at how easy this upgrade was to do, the increase in performance, and the simplicity it brought to my storage needs.

Thanks again to Tom and his guide for giving me the information and courage to attempt the upgrade myself.

If you are interested, I have posted a 20mb zip file with full size images of all the pictures in the guide.