iMac 2008 (MB325LL/A)

iMac Upgrade – How to upgrade your iMac’s RAM and hard drive

In iFix by andre3 Comments

My iMac Passed-out

My trusty 24-inch iMac (MB325LL/A) had been running without a single problem for the past 4 years. Oddly, two weeks ago, it started rebooting itself and that Mountain Lion became groggy. I later discovered that it was a failed hard drive causing all the problems. Obviously I needed to replace the defective disk, but it seemed smart to consider an iMac RAM upgrade and an iMac hard drive replacement to add more disk space.

iMac Upgrade?

My iMac 2008 came with 2GB RAM and a 500GB Hard Drive. Nowadays, a 2TB hard drive costs just a little over $100 and for another $50 you can upgrade your iMac RAM from 2GB to 4GB. Because my iMac was already out of warranty, I chose DIY (less than $200 in total) over paying Apple 3x more to get it fixed.

If you too want to upgrade your old iMac (iMac 2008, iMac 2009),  follow the procedures below. I will show you how to add memory to iMac and how to replace iMac hard drive. I promise I will keep my instructions as concise as possible.

Upgrade iMac RAM, Hard Drive

Get Tech Specs

Before you start doing any iMac RAM or hard drive upgrade, you first need to find out some technical details about your iMac – model number, memory and hard drive specs. The easiest way to find technical specifications for all iMac models is by searching your iMac’s serial number on Apple’s Tech Specs page. Once you find the tech specs for you iMac model, write down the information for memory and hard drive. For my iMac, the memory is 2GB (two 1GB SO-DIMMs) of 800MHz DDR2 SDRAM; the hard drive is one 320GB Serial ATA4; 7200 rpm.

Find the Perfect Parts

Pay close attention since this step is crucial. It is critical for you to find the correct memory, hard drive for you iMac. Not only do they have to be compatible to be installed, you also need to make sure the components you get won’t cause your iMac to overheat. Once you open the case of your iMac, you will be surprised how compact the inside is, there is hardly any room between the components. To not damage any of these components you need to find a hard drive that runs cool and is preferably silent. The good thing is I have already done the research for you. If you use the memory and/or hard drive I suggest below, you shouldn’t experience any of the problems I mentioned above.

  • iMac Hard Drive
    The best iMac hard drive I found is: WD Green 2 TB Desktop Hard Drive (WD20EARX).  As Jan 2013, there is a newer model of this drive with improved performance – WD Green 2 TB Desktop Hard Drive (WD20EARX). FYI, this hard drive won’t give you the best performance compared with other 3.5 inch SATA drives on the market. However, it is perfect for iMac because it runs cool and quite and uses less than 40% power consumption; it’s a green drive.
  • Memory for iMac
    The biggest mistake people usually make when upgrading iMac RAM is choosing the wrong RAM. You need to verify the RAM you’re going to buy has the same tech specs  as what you obtained from Apple. Examine the following carefully. It is DIMM or SO-DIMM? Is it DDR2 or DDR? Is it 800MHz or 667MHz. If you want to avoid any potential problems, you need to find the exact match. For iMac 2008, MB325LL/A model (2 GB SO-DIMMs of 800MHz DDR2 SDRAM), the best memory I found is Kingston Apple 4GB Kit.

Get the Right Tools

In  order to successfully operate on your iMac. You’ll need the following tools:

  1. Torx screwdrivers: Torx T6 and  Torx T8
  2. Very small philips head screwdriver 
    I highly recommend you get Mac Repair Tool Set which includes both Torx and Philips screwdrivers for repairing MacBook and iMac.
  3. Couple of suction cups (see pictures. Tips: try find those at dollar stores)
  4. Large towel
  5. Compressed air for clean up

Step by Step Walkthrough on iMac Upgrade

  1. Unplug your iMac and carefully place it on its back on a soft towel. iMac_back
  2. Place at least two suction cups on the glass to lift it up. (The glass is held in place by magnets around the frame. The suction cups make it really easy to lift and I don’t recommend you use a screw driver or anything which could damage the glass!). Please at least two suction cups on the glass to lift it up.
  3. With the glass out of the way you can see the monitor. The aluminum frame is held in place by a bunch of screws. Use the T6/T8 to remove them (Note there are screws of two different lengths, so make a note of where the long ones were so you can put them back into the same holes later!) The aluminum frame is held in place by a bunch of screws.
  4. Remove the RAM cover on the bottom, it hold the bottom of the aluminum frame in place.

    Remove the RAM cover on the bottom

  5. CAREFULLY remove the aluminum frame and watch for the tiny cable that connects the iSight camera. We chose not to disconnect it and simply placed the frame onto the upper part of the towel. Remove iMac Frame
  6. Now you need to remove the screws that hold the monitor in place. Place them separate from the other screws.Remove Monitor Screw
  7. The monitor is connected by 3 cables, 2 towards the bottom of the iMac and the power supply on the back. The cable near the fan easily unplugs, for the other (see picture) you have to remove the 2 screws first then then pull on the little tape attachment and it will pop right up. Remove Monitor Cable MonitorCableScrews_mark
  8. Now it is time to lift the monitor. Please be careful, as the power supply cable is still attached on the LEFT side on my model. If you are unsure lift it gently and see which side the cable is attached on. The cable is long enough for a second person to hold the monitor up for you to switch the hardrive.
  9. Remove the heat sensor from the top of the hardrive. It is just glued on and if you are lucky you can stick it right back onto the new one; if not a drop of glue or some tape will do.
  10. Unplug the hard drive cables – This is easy!  HD_Cables_mark
  11. With the heat sensor removed push the big black lever towards the bottom of the iMac (towards the hardrive NOT the back of the computer!) which unclips the hardrive holder and lets you pull the hardrive right out. RemoveHD_mark
  12. Unscrew the 4 screws on the sides of the hardrive because you will need to attach the hardrive holder to your new drive.
  13. Install the holding mechanism on your new hardrive, the same way it attached to the old drive.
  14. To put the hardrive back press the black lever towards the bottom of the iMac to lock the drive into its place. Re-connect the cables. RemoveHD._mark_in
  15. Re-attach the heat sensor to the top of the new hardrive and put the foam back on top of it. If it doesn’t stick well, just use a drop of glue or some tape.
  16. Put the monitor back into the frame and secure it with its screws.
  17. Reconnect the 2 cables, one simply plugs in, the other one plugs in and is held in place with 2 screws, so you need to screw those back in.
  18. Watch for the iSight cable when you put the aluminum frame carefully back in its place and secure it with the screws you took out. Still remember where the long screws belong?
  19. Put the glass back in its frame. There are small guide pins that make it really easy to position it correctly and the magnets will hold it in place.
  20. The final step is to pull out the two old memory modules by simply pulling on the little plastic strips and replacing them with the new modules you purchased. Screw in the little cover and your iMac upgrade is complete! RAM

If anytime, you have difficulties deciding which cable or screw to take off, read the above instruction again or ask me by commenting below. Remember being patient and don’t rush. Slow and steady wins the race.

Image Credit: ian munroe


  1. I was wondering about after upgrading both the hard drive and the ram memory to the same pieces mentioned; what is the newest or most recent macos that I am able to install to this same 2008 model imac?

  2. Hey, How are you doing? My name is Iverson and i recently replaced my hard drive (it stop working) . I upgraded it to a 2tb hard drive and now when I turn on the IMAC i am not seeing the hard drive listed. What do you think is the problem?

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