Stayin’ Alive: Upgrading the CPU, Hard Drive, and RAM on a 2006 iMac

The days of upgrading modern Macs are practically gone. As a tradeoff for ever thinner and lighter products, Apple customers have accepted the reality that when their new Mac gets long in the tooth, it will find its way to the dumpster (or, hopefully, an electronics recycler). But it wasn’t always this way. Older Macs frequently offered multiple upgrade paths, with varying level of difficulty. So don’t toss or sell that old Mac, upgrade it!

Upgrade 2006 iMacRecently, I did just that. While visiting my parents, I rescued a 2006 20-inch iMac from their basement. It was a bit of a homecoming for the system. The Mac was originally mine, purchased in college as an upgrade to my underpowered first generation Mac mini. It was my first Intel-based Mac, my first OS X Tiger system, and my first “dual-core” computer (not counting Intel’s early Hyper-threading options).

The Mac served me well, but I was quickly drawn to the Aluminum iMacs released in late 2007, so I upgraded and sent the neglected 2006 model to live with its grandparents. After picking it up again the other day, it was still in great physical condition, but was starting to show its age. The 250GB hard drive was making more noise than I was comfortable with, and the operating system, now OS X 10.5 Leopard, wasn’t able to run any modern software. The 2.0 GHz Core Duo CPU was fine for basic tasks, but its 32-bit nature, and 2GB of RAM also greatly limited my software options. Instead of wiping the system and selling it for maybe $100, I decided to see if a major overhaul could give this system new life.

Despite my ambitions, there were some constraints that were unavoidable. As we’ll discuss, I was able to raise the default RAM limit, but only to 4GB, and the built-in SATA connection was limited to a measly 1.5 Gbps. Further, the system’s GPU, a Radeon X1600 with 128 MB of memory, was soldered to the logic board, with no practical hope of removal.

Still, the 2006 iMac was uniquely suited for this upgrade project. Not counting the Mac Pro, it was one of the last Macs with a socketed CPU, meaning that processor upgrades were possible if you could dig your way though the tightly-packed design of the system’s innards (Update: As many have pointed out, certain iMac models as late as the current 2013 generation also preserve the socketed CPU). The iMac also utilized a standard SATA connection for the hard drive, allowing for an easy swap without consideration for the proprietary temperature sensors found on newer models. With these items in mind, I settled on the following upgrades:

Upgrade 2006 iMac Core 2 Duo

CPU: Intel Core 2 Duo 2.33 GHz T7600
RAM: 4GB Crucial DDR2 667 MHz (PC2–5300)
SSD: 256GB Samsung 830
SSD Adapter: Icy Dock EZConvert
Thermal Paste: Arctic MX–2

Some notes about my component selection: I went with the fastest compatible CPU, and that’s the T7600. They’re still fairly pricey when purchased new (if you can find them), but I picked up a used one from a reliable eBay seller for about $50. So make sure to look for a good deal in order to keep this upgrade project economical.

Speaking of economical, the Samsung 830 SSD is overkill for this project, but I had it available from a previous build. Since the iMac only uses a 1.5Gbps SATA interface, look for the cheapest SSD you can find from a reliable manufacturer. I also had the RAM available from an upgraded Mac mini, so I saved some money there. In the end, the only components I had to purchase were the CPU and the Icy Dock SSD Adapter, which cost about $15. That brought my total to around $70 with shipping. Had I needed to purchase the SSD and the RAM, the cost would likely have risen to about $300.

The Upgrade

The first thing we did was clone the iMac’s internal hard drive to the SSD using a SATA to USB adapter. We toyed with the idea of starting from scratch with a fresh install, but there were lots of files on the system and we wanted to make sure we had an opportunity to save any needed data. We knew we’d be upgrading the operating system later, and figured that we could always nuke and pave at that point once we made sure the hardware upgrades were successful.

2006 iMac Upgrade Core 2 Duo SSD

When it comes to the hardware upgrades, we’re just going to give you one word: iFixit. This great website has hundreds of beautifully detailed guides for repairing all sorts of computers, gadgets, and other electronics, including the one we needed for our 2006 iMac. These guides are so good that, during my time as an Apple technician, we frequently relied on the iFixit Guides over the Apple internal repair documentation.

2006 iMac Upgrade Core 2 Duo SSD

There’s no sense in repeating the steps here, but if you follow the guides at iFixit, most upgraders will have no trouble performing the CPU and SSD swaps. We’ll just give you these words of advice:

  • Be careful with the data connectors on the logic board. You’ll need to disconnect several of them, and they can be quite fragile and brittle on these older machines. Use spudgers and tweezers wherever possible to avoid accidentally pulling out individual wires from the connectors.
  • Use tape to keep disconnected wires secured outside of the open system. You’ll be removing and then reinserting the entire logic board, and it’s easy for some of these wires to fall into the chassis when you’re not looking and get inadvertently covered by the logic board when you put it back. There’s nothing worse than getting everything put back and screwed into place only to realize that your final data connection wire is missing and trapped underneath your newly reinstalled components.
  • Make sure to clean the old thermal paste from the tops of the CPU and GPU as well as from the heatsink. Then reapply fresh thermal paste to both chips before reattaching. Even though we’re not dealing the with GPU, you’ll see that the GPU and CPU share the same heatsink, and you always want to reapply thermal paste whenever you remove a chip’s cooling apparatus.
  • Don’t install the upgraded RAM just yet. We’ll need to update the Mac’s firmware first or else the system won’t boot (more on that below).

2006 iMac Upgrade Core 2 Duo SSD Benchmarks

Overall, the upgrade took about one hour from start to finish. Experienced computer technicians will likely be able to do it even faster. We put everything back together, buttoned the system up, held our breath, and pressed the power switch. After a brief pause, the familiar Mac startup chime sounded and the iMac booted right up. Success!

2006 iMac Upgrade Core 2 Duo SSD

To check the status of the upgrade, we headed to the System Profiler. Sure enough, our Mac reported a 2.33GHz Core 2 Duo CPU and a 256GB solid state drive. Now we had to deal with the RAM.

Pump Up the RAM

By default, the 32-bit Core Duo iMac platform only supported 2GB of RAM. Now that we had a 64-bit Core 2 Duo, we were eager to upgrade the RAM to a maximum of 4GB, but we needed to convince the rest of the Mac that it could handle the larger RAM total. To do this, we’d need a firmware update.

While it’s possible to do this manually, the user MacEFIRom over at the netkas.org forums created a handy app that performs the upgrade for us. Basically, it takes the firmware from the late 2006 Core 2 Duo iMac and applies it to our early 2006 Core Duo system. The Macs were practically identical except for the platform switch to the Core 2 Duo CPU, so the firmware upgrade works beautifully.

2006 iMac Upgrade Core 2 Duo SSD Firmware

To use the firmware updater, simply download it (you’ll need to register a free account at the netkas forums to see the download link), and run it on the 2006 iMac. The app will create a RAM disk to prep the firmware files and then give you instructions on how to apply the update, which involves restarting the Mac and then holding the power button until the status light blinks. The update takes about 3 minutes and worked without a hitch on our system. After it’s done, you can shut the Mac down and install the 4GB RAM upgrade.

2006 iMac Upgrade Core 2 Duo SSD Firmware

With the firmware update complete, our Mac reported itself as “iMac5,1” instead of “iMac4,1” and saw the full 4GB of RAM. That was it; our elderly and slow 2006 iMac was now decked out with a “new” 2.33GHz Core 2 Duo CPU, fast SSD, and 4 GB of RAM. It was time to deal with the software problem.

Cool Software, Bro

2006 iMac Upgrade Core 2 Duo SSD Snow LeopardOur iMac originally shipped with OS X 10.4 Tiger, but was running 10.5 Leopard when we picked it up. Officially, 10.6 Snow Leopard was the latest supported operating system, but there were many reports of users getting 10.7 Lion to install. Even though Lion would give us access to things like iCloud, it simply wasn’t the greatest operating system, and we believed that Snow Leopard would run better on the hardware.

A Snow Leopard system, updated and running the Google Chrome browser, would likely meet our needs just fine. So we dug up our old Snow Leopard installer, upgraded the OS, and then performed all necessary software updates to bring the system up to 10.6.8. Some quick testing confirmed our initial predictions. Microsoft Office 2011, Skype, Chrome, and Plex all worked great on Snow Leopard with our upgraded hardware.

Benchmarks

Our initial testing revealed noticeable improvements in performance; the system booted faster, apps launched in a flash, and everything seemed significantly smoother. We anticipated the need to quantify these changes, so we ran benchmarks both before and after the upgrade.

The SSD obviously helps with items like application launches and boots. While the iMac doesn’t boot nearly as fast as its modern counterparts, the installation of the SSD still shaved 12 seconds off of our cold boot test.

2006 iMac Upgrade Core 2 Duo SSD Benchmarks

Pure read and write speeds also saw an unsurprising bump. Write speeds were 160 percent faster with the SSD, while reads were 132 percent faster. Note that this is only a comparison of the specific original hard drive in our iMac with the new SSD. As we mentioned earlier, the hard drive was quite loud, and may not have been operating at its theoretical maximum performance.

Looking at Geekbench, we saw excellent performance gains of between 18 and 53 percent. Note that these scores are from Geekbench 2. Our iMac didn’t meet the system requirements of the new Geekbench 3 test.

2006 iMac Upgrade Core 2 Duo SSD Benchmarks

Maxon’s Cinebench tests both GPUs and CPU rendering performance, but our Radeon X1600 GPU was unsupported, so we were only able to compare single- and multi-core CPU scores. Both saw improvements of about 34 percent with the upgrade.

2006 iMac Upgrade Core 2 Duo SSD Benchmarks

Back From The Dead

Most of these numbers pale in comparison to current generation Macs, and that’s not surprising. We knew we wouldn’t be creating a powerhouse with these upgrades, but what we found is that our “new” iMac now makes a respectable secondary computer. The Core 2 Duo CPU and 4GB of RAM can handle most basic productivity and entertainment tasks, and the SSD makes loading apps feel almost as fast as they do a modern computer.

2006 iMac Upgrade Core 2 Duo SSD

Whether the upgraded iMac ends up as an extra system in the guest room, a fun play computer for the kids, or just a backup for when a main Mac is out of commission, this upgraded system is definitely usable, and we couldn’t have said the same thing pre-upgrade. In addition to the excellent learning experience of upgrading an Apple product, we’re also happy to keep a computer “in the field” and out of the landfill.

Have you upgraded your older Mac recently? Or are you now inspired to undertake the project? Let us know in the comments!

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  • UnaClocker

    Was that the only processor upgrade option? Could you have gone faster, or with a quad core?

    • http://www.tekrevue.com/ TekRevue

      No, not practically. Socket support, TDP considerations, and firmware support limited me to the Merom architecture. I suppose it would be possible to find the logic board from a newer Mac and hack it into the chassis of the 2006 iMac, but that would be a major undertaking well beyond the scope of this project. Plus, that’s really less of an “upgrade” and more like taking the body kit of a Honda Civic and wrapping it around a Ford Mustang.

  • Ninjapork

    I’m thinking of upgrading the ol’ imac 24″ 2007 model. It was the last of the “white” series, and later that year Apple released the aluminum ones. Probably gonna switch out the HDD for a SSD, and maybe try and get more ram in it.

    • http://www.tekrevue.com/ TekRevue

      The SSD is still the best upgrade one can make on an HDD-based system. Even if the total throughput is limited to SATA 1 or 2, the random access times make a huge difference. Let us know how your upgrade goes!

  • Steve

    Found my old 2007 Mac mini in a box. Decided to give it to my buddy. We added 4GB of ram, OS 10.7 and an 120GB SSD. Now it’s pretty fast. Boots in 21 seconds vs 1 min with the original HDD. It’s not a power machine but It sure beats his Mac mini G4.

    • http://www.tekrevue.com/ TekRevue

      Awesome! Recycle & reuse FTW!

  • Shawn Shomaker

    While you’re at it you should alsa install higher res laptop lcd and adaptor from http://www.realmacmods.com

  • brucerb

    Although you have 4 GB of RAM installed, you only have 3 GB of that available for applications and the OS to use. The 3 GB usability limit may show up in Activity Monitor. My recollection, from when I upgraded a late ’06 iMac to 4 GB (which I no longer have) is that there is little to no advantage to installing 4 GB instead of 3 GB in these machines (unless, as was my case, 4GB happens to be what you have available). There may be a tiny speed benefit from a matched pair (2+2 instead of 2+1) of RAM boards. It’s also possible that the RAM used by the graphics card will come out of the otherwise unused 4th GB, which would free up a bit (128k?) of RAM (I can’t find a reference for this but seem to recall reading such a claim).
    Great article!

  • Gwaiguy

    Recently upgraded the HD on my late 2006 5.1 iMac, and came here to see
    if there is a way to upgrade it to be compatible with Mavericks. I only
    use it as a back up and home studio solution for my music software and,
    having just upgraded the main play out lap top I use for DJing to
    Mavericks to enjoy the features of a newer DJ software, find that the
    song file tags modified in the newer software are not back compatible
    with the older version on the iMac :-(

    Seems like Mavericks (if
    you need to use it, and is only back compatible to the mid-2007 iMac) is
    an old, even intel based, Mac killer. Shame.

    • Villy Jørgensen

      iMac 5,1 Intel Core 2 Duo, 2 GHz (Late 2006), 2GB RAM, 250GB Samsun 240 SSD.
      Installed Mavericks, you need to hack the installer. Some features are missing. iPhoto is unable to display pictures in full size, it only shows a black screen. iMovie wont install, missing graphical feature.
      OS X 10.6.8 boots in 20s, Mavericks is 50% slower.
      Went back to 10.6.8 but is missing Pages.
      PS. Be careful when using compressed air to clean the fans, destroyed the CD-ROM fan due to too high rpm.

  • Beth Margolis

    I just want to upgrade my hard drive on the same computer as yours (IMAC 5,1). I have already upgraded my RAM. If the hard drive is the only thing I replace now, can you recommend one for me?

    • http://www.tekrevue.com/ TekRevue

      Hi Beth,

      Are you looking for a mechanical hard drive (HDD) or a solid state drive (SSD), and in what capacity?

      For HDDs, I’ve had good experience with the Western Digital Black series. You can get a 1TB drive for about $80 all the way up to a 4TB for around $250. There are cheaper drives available, but I’ve learned not to skimp on hard drives, as they’re arguably the most important part of a computer.

      If you’re looking for SSDs, try the 240GB Crucial M500 for about $120. I also like the Samsung 840 EVO series, but they’re more expensive. In either case, the drive is faster than the SATA bus in your Mac, but they’re reliable and could likely be moved to your next computer when you go to upgrade in the future.

  • Alec J

    Hey!
    I snagged an identical iMac off of eBay in need of some love, and after re-replacing the LCD (previous owner bought the G5 LCD as a replacement and wondered why it didn’t work… it’s the same dang panel but different sub-model? All of the connections are the same, too… but it just doesn’t fire on!) I have decided to make it *almost* the best it can be.

    Almost? Well, I am throwing in an unused, technically “old” Hitachi 500GB drive I am not using (so no SSD). I took out the included 512MB stick of RAM and inserted the two 1GB sticks I took out of my old Dell Vostro 1500 (put in two 2GB sticks in the Vostro not too long ago). So now I’m at my maximum RAM for now (still on the original Core Duo).

    Here’s my biggest note:
    The T7600 is the fastest thing you can put in this. Indeed. There’s also the T7400, at 2.16(?)ghz, except I’ve only really seen one or two on eBay… weird… And then there’s the T7200 at 2.0ghz. SO. If you jump on eBay right now, one will pay a pretty hefty sum for a T7600. Huge bummer. In my case, my $60 machine will turn into a $140+ machine just doing this upgrade. My solution? Snag the T7200. Sure, I’ll be missing out on 300ish megahertz BUT instead of paying something pushing $100 for “the best” processor, I’m going to spend around 1/8th that. I got my T7200 for $13, free shipping. Seller seemed reputable. I think the normal price is definitely under $20, around $17 after shipping. Extremely good deal. Especially for what this machine will be used for (and even if I really try to torture it with tasks!), I highly doubt I would even be able to tell the difference between the 2.0 and the 2.33 CPUs. But I’ll easily feel it when I sit on my wallet.

    So… Short version:
    Want to upgrade to 64-bit (opens up proper Lion installs) and all of that jazz, but don’t want to spend too much? Check out the T7200. Deal of the century! Especially for me. :)

    • Alec J

      Also. I’m sure once I am done with this machine, this previously eBay “garbage”, I will have spent the same if not more than it is currently worth.
      But there’s absolutely nothing like fixing something yourself, bringing it back from the dead, and keeping it out of the trash can. I feel so wonderful right now, typing on this iMac. Your short note at the end of the article mentioning that you are saving something from the trash – I think that is a priceless situation. Someone, or multiple people, out there (in my case) used this iMac a lot. They had a great time, played games, wrote term papers, watched funny videos… it was a workhorse at the very least! And for it to be thrown away… That’s just unacceptable!

      Mine was obviously mistreated by its last owner, at least…
      I had some overheating issues yesterday and decided to take the heatsink off and put new thermal paste on just for good measure. I realize now the previous owner took the CPU heatsink off at some point… because he/she screwed up the retention bracket at the end of the heatpipe (the bracket that holds the actual fins steady). I did this little procedure (disassemble, new Arctic Silver, reassemble) and my temps went from ~52*C… IDLE…. and almost 80*C full load (random “unplug” style shutdowns, etc) to (drum roll) 34*C idle and 53*C full load. So I basically made my full load the same as my old idle! Whoa! Just fresh thermal paste and, I assume, proper heatsink assembly/retention. I was BLOWN away.
      When I did this, I booted the machine up that first try. my tempts were around 50. I thought, “Well, that didn’t do anything… oh well.” and then I realized… BOINC was still running. It started at boot, and was loading the processor. I turned it off, and in just seconds I dropped to 36..34… 33…32*C (the room was pretty cold at the time). I was speechless.

      • Alec J

        Little update. CPU install went great, yes, but eventually I still had the “pull-the-plug” shutdown problems. My temps for CPU and GPU were still, and still are, GREATLY reduced.
        I ended up replacing the power supply after finding that someone on BadCaps.net had a similar problem (with little/no response, and no resolution on a component-level repair). The replacement seems to have fixed everything completely.

        I also upgraded from Snow Leopard to Lion. This was easy, I just used a borrowed MacBook Pro (2009ish?) and put my iMac into Target Disk Mode with the proper Firewire cable. The MacBook saw the iMac as a drive (as expected) and I easily booted into the iMac (from the MacBook) and subsequently started and finished the Lion installer app. I had to delete this one file… System/Library/CoreServices/PlatformSupport.plist – this allowed the iMac to boot with the new Lion install. Worked perfect! Then I updated Lion through the normal system update means, and upon rebooting my iMac brought up the “no!” signal (circle with a cross through it, like (/) or so). I then put it back into target disk mode, booted the laptop from the iMac drive (same as when I installed Lion initially) and everything was fine… So I then deleted that file AGAIN and everything was just peachy. iMac has been running most of the day on a fully-updated Lion install. I think it was only the true “system update” (from 10.7.0 to 10.7.5) that added that PlatformSupport.plist file again, and I had to boot again into Target Disk mode to delete it.

        Computer runs great! Even with (currently) only 2GB ram.

        Cheers everyone,
        -Alec

  • TM

    Excited to do this my old workhorse. I will have a good tech guy I know help me with it. I can totally see myself losing or tearing something off. Thanks for the help!

  • Zack Taylor

    Can I upgrade the cpu without the firmware tool? will it still work?

    • http://www.tekrevue.com/ TekRevue

      Yes, but you won’t be able to address more than 2GB of RAM.

  • Chris Greenhough

    So tempted (and inspired) to try this. I have a 2006 white iMac 4,1 which was a birthday present and still my main computer for working at home. Of course it struggles with only 1.5GB of RAM (no surprise) and will not run Lion unmodified. This could give me a new lease of life. I would be tempted to retain Snow Leopard as it is quick and stable, perhaps with an external drive or another partition to run Lion when I need apps that require it. I previously considered building a Hackintosh but decided against the time and expense required for now. Besides, all I’ve ever done before now is install new RAM.

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