How and Why to Upgrade Your Mac’s Hard Drive

As a follow up to our article on upgrading your Mac’s RAM, this article will outline how to go through the same process to upgrade your hard drive.

We’ll begin with a brief discussion on why upgrading your hard drive will improve your system then move on to the pros and cons of mechanical vs. solid state drives. We’ll conclude with a step by step tutorial on finding and purchasing the right HD for your Mac and point you to some instructional guides outlining the installation process for your specific model.

A Tale of Two Variables

There are two primary reasons to upgrade your hard drive: storage and performance. The first one is simple to understand. If your hard drive is constantly filling up and forcing you to offload or delete files, then you probably need a bigger drive.

The second variable is much more complex and can, in fact, get quite techy. As we’ve learned, the performance of your Mac can largely be improved by upgrading your RAM. However, the hard drive also plays a major role in the speed of various activities such as data access and startup times.


A Mac Hard Drive

The primary factors related to the speed of your Mac’s hard drive are RPM and cache size. Rotations per minute (RPM) refers to how fast your hard drive is spinning and directly correlates to how fast it can read and write data. Though there are plenty of arguments out there regarding how easy it is to be deceived by a drive’s RPM, they are all supremely technical in nature and sound like a foreign language to anyone not familiar with terms like IOPS and partial stroking. For the purposes of this article, we’ll assume that more RPMs equals higher performance. For example, a 7,200 RPM hard drive will perform better than a 5,400 RPM drive.

The buffer cache refers to a temporary storage area that is used to enhance the drive’s performance. According to, “when the computer requests data from the hard disk if that data is in the cache, there is a performance boost directly related to the speed of the cache.” So generally speaking, the larger the buffer cache size, the better the performance of the drive.

Solid State Drives

The information above is relevant for typical hard drives, meaning those that actually spin. The basic idea is that a disc full of positively and negatively charged area spins under a read/write device called a head. As with anything containing moving parts, these devices are quite prone to failure. In fact, these precariously spinning objects have one of the highest rates of failure of any component on your machine. It’s unfortunate that the part likely to die on your Mac first is the part holding all of your valuable data.


A Mechanical Drive and a Solid State Drive

Solid state drives are a pricey alternative that contains zero moving parts and therefore a much lower chance of something going wrong with the device over time. As an added bonus, there is no initial start up time as there is no disk to get spinning. Furthermore, reading and seeking times can be in the hundreds of times faster with SSDs than mechanical disks (source).

The primary downside of SSDs is currently their price but there are also arguments regarding information recovery that can be perceived as either a pro or a con. Deleting files from a solid state drive leaves a lot less residual data which can make it difficult or impossible to recover lost information. On one hand, this makes these drives much less of a security threat to anyone concerned about thieves pilfering their drive for information. On the other hand, sometimes tragedy strikes and you actually want to be able to recover lost data and a drive that makes this impossible will not be pleasant to own in this circumstance.

Below we’ll look at both options when examining how to purchase a hard drive. We’ll go step by step through the process of how to discover which drive you need and where to find a replacement.

Step 1: Learn About Your Mac

As we did with your RAM, the very first thing you need to do in your hard drive upgrade process is to find out the technical information you’ll need to know to purchase the right hardware (this section will be a little redundant if you’ve already read the RAM article but is helpful to newcomers). To do this, click on the little Apple icon in the very top left of your screen and select “About This Mac” from the options. The following window should pop up.


About This Mac

As you can see, this handy little window tells you which version of OS X you’re running and provides info on your processor and memory (RAM). The picture above shows you that I have a 2.16 GHz Intel Core 2 Duo process with 3GB of RAM. Don’t worry in the slightest if none of these numbers make any sense to you, just jot down your processor information from this window (a quick screenshot would suffice as well). We’ll use this information later to determine which hard drive to buy.

After you’ve saved the information from the about window, hit the button that says “More Info.” This will take you into an application called “System Profiler” that contains all kinds of technical information about your Mac. As you can see below, down the left side there is a series of categories. Click on “Serial-SATA” under the “Hardware” heading (most newer Macs contain SATA drives, older models might contain IDE/ATA drives.).


About This Mac

Here you can see the current model, serial number and capacity of the drive currently in your system. As you can see in the screenshot above, I’ve got a 120GB drive with only about 20GB free. It’s about time for me to upgrade! As we stated above, RPMs are something we want to pay attention to and they are not represented in this information. The easiest way to find this out is to jump over to EveryMac.

Step 2: Find Your Mac on EveryMac

Again we’ll follow the same process as we did in the RAM article to locate the right Mac on This website features tons of useful information about every Mac in existence and is always my first stop on an upgrade quest.



Scroll down until you see a list of Macs separated by series, year, processor, etc. under the heading “Recent Apple Specs.” Now click on the Mac you own under the “Series” heading. For example, I clicked on “MacBook.”


Find Your Mac on the List of Models

Next you should see a list of the all different versions of your Mac that have ever been released. This is where your processor information from the Apple “About This Mac” screen will come into play. As you can see in the pic below, I found my 13″ 2.16 GHz Macbook and clicked the dropdown for a quick breakdown of my specs.


Click the Arrow to Open the Dropdown Menu

Next, click the link at the bottom of the dropdown for complete specs on your selected machine. This will take you to an entire page of information devoted to your specific model and version of Mac. Here you can read all kinds of interesting information about your Mac and what made it unique when it launched. Scroll down past all of this info to the section of the table labelled “Standard Hard Drive.”


Find Your Hard Drive's Specs

As you can see in the screenshot above, the standard hard drive in my model is a 120GB 5400 RPM drive. Armed with this information, let’s jump over to OWC to find a decent upgrade.

Step 3: Finding and Purchasing the Right Upgrade

Now that you have a general idea of what’s currently in your Mac, stop by Other World Computing to see if you can find something better. On the home page, click on the “Internal Storage” button in the navigation at the top. This should bring up the following screen.


OWC: Choose Your Category

As you can see, they make it really simple to choose the category of drive you’re looking for. In my case, I’m looking to upgrade my MacBook, so I’ll click on the laptop hard drive option. Choose the option that matches the specs you saw on everyMac and in your System Profiler window.


Select Your Drive

The top of this page informs me that the hard drives here will work on all 2006 and later models, including all MacBooks. This provides me with additional confidence that the drive I select will in fact work with my machine.

As you can see, I have the option to either go with a mechanical drive or a solid state drive. True to what we discussed earlier, the solid state drives are quite a bit more expensive than the mechanical drives so make you’re confident that you won’t be happy with a traditional drive before upgrading to an SSD.

The traditional drive options are actually quite affordable. I can upgrade my 120GB 5400 RPM 4MB cache drive to a 500GB 7500 RPM 16MB cache Hitachi drive for about $100. That should provide me with some significant performance upgrades and instantly solve my quickly depleting supply of available storage.

MacRumors Hard Drive Quick Reference

If you know what you’re doing and don’t want to go through all the steps above to find the replacement drive you need, I’d recommend taking a look at the quick chart of hard drives for various Mac models from Mac Rumors.

Other Places to Buy a Hard Drive

Always be sure to shop around to get the best deal. Many times, OWC will have the best price but there are definitely other options to check as well. Here are four other stops to make before you make a decision.


New Egg


Crucial (SSDs)


Mac Improve



Step 4: Installation

Every Mac model is different and will have its own unique process for finding and removing the hard drive. Before I’ve compiled a list of links to some instructional videos that will show you exactly how to replace your specific Mac’s drive. For complex tasks such as replacing a hard drive, I find video tutorials to be much more helpful than a static instructional guide as you can actually view the process as it’s happening and can therefore be confident that you are doing it right.



Mac Pro/G5


Don’t see your model? No problem, this is just a small sample of OWC’s super helpful instructional videos. You can view a full list here.


To sum up, upgrading your Mac’s hard drive will not only increase your available storage, but will also improve your machine’s performance.

Your two options for hard drives are mechanical and solid state. Traditional mechanical drives are far more affordable but suffer from wear and tear as time goes on and are therefore prone to failure. Solid state drives by contrast are an expensive alternative with faster startup and seek times. Though many believe that SSDs represent the future of hard drives, they can be pretty uneconomical at this point in time if you’re looking for a simple and affordable upgrade.

I hope this article has emboldened you to take on the intimidating task of upgrading your Mac’s HD if you’re in the market to do so. The videos above really break it down nicely and can make the entire process relatively easy if you have even the slightest bit of computer hardware experience.

Let us know in the comments below if you have any other basic hardware or software instructional guides you’d like us to put together. We’re eager to hear your ideas!


Add Yours
  • Great. My problem is not why or how. Is with what. I’ll check those links.

  • Awesome post! I been wanting to do this for quite some time but never knew how. Thanks again!

  • How appropriate. my macbookpro internal drive just died last Friday. No real reason why; had previously been working great. After it died, mac still “saw” it but the drive was grayed out and unmountable.

    fortunately for me, it was still under warranty. Called appleCare support, had me try a few things and eventually deemed it necessary to be replaced. I literally took it down to the local iPlace store that was a registered service center this past tuesday at lunch. They call me that afternoon and let me know that they already ordered a new replacement drive from Apple (actually got a 250 gb drive out of it whereas the old drive was only 200gb). They then called me in the evening of the very next day and said it had been replaced and was ready for pickup. didn’t cost me a dime. a great turnaround in my opinion.

    also, I had kept time machine backups as well as a bootable partition (thanks superduper) on an external hard drive (actually internet drive with an icy dock external enclosure). so I’m back to where I was and up and running within a week of the drive failing.

    the point of my post? the AppleCare warranty is worth it. (2nd time dealing with them as my battery had started coming unglued a while back — the shipped a new replacement battery next day at no charge to me).

    And when my warranty runs out, I’ll be sure to hit up this article if my new internal drive should ever fail.

    of course, there is still the underlying issue of why my mac parts are having such issues in the first place, especially since the macbookpro is barely 2 years old. but alteast it has been softened a little with their excellent support and warranty procedures.

  • Have a look at
    There you will find detailed repair manuals for every mac.

  • The links you have for installing a new hard drive in an iMac are actually links on how to install RAM. Just a heads up.

    • Good catch! Strange that OWC left out the HD videos. I updated the links with some YouTube versions.

  • installed a new hdd in my imac in january following directions. very thorough walkthrough. everything went great until the reassembly. i had the wires from the isight camera on the wrong side which caused the protective glass panel to not quite fit right in the aluminum frame and crack at the very last minute.

    I had to order a new protective panel from apple, and with installation was only ~$50 US. not too bad for my screw up. just make sure you note the placement of everything and put it all back just as it was before placing the outer panel back on.

    with that said, I don’t know if I would attempt it again on an imac, but that’s just me. if you do, make sure you get some good suction cups to remove and reinstall the protective outer screen.

  • Thanks.
    One little thing: Is there finally hardware encryption for the Mac? Or is the Mac EFI still too dumb to support it?
    Since FileVault is useless and actually dangerous, PGP slows down your Mac and disables hibernation and automatic sleep, it would be nice if finally there’d be a usable encrpytion solution for Mac.
    PC users can just buy one of the hardware encrypted harddrives and enjoy inobstrusive encrytion.
    Apple still doesn’t seem to care about business users and wants lawyers, managers and journalists to run around with unprotected or half-ass protected data on their harddrives. It’s beneath me, why?

  • Hi, I have a question. Does SSD’s produce less heat than the mechanical ones ?

    I have a 2009 15″ Unibody MBP, but the part where I rest my left hand while using the keyboard, gets too hot to basically do anything on the laptop. I guess that is where the hard disk is placed ? This is very annoying. Will upgrading to an SSD solve this ?

    • I had the same issue. I downloaded Fan Control 1.2 (Not SMC Fan control) and set the fan more aggressively. It was always cool after that.
      And no, the left side is the battery, hard drive is on your right (Hard drive is on the same side as the DVD, Battery is on the same side as power.

  • I maxed out the standard 120GB drive that came in my 2008 MacBook and decided to upgrade to a larger one. I purchased a 500GB Western Digital Scorpio Blue, a Snow Leopard DVD, and the required Torx T8 tool to swap the mounting brackets of the MacBook HD. I ran one last Time Machine backup, pulled the old drive, installed the new one, installed a fresh copy of Snow Leopard, and ran the Migration Assistant to restore everything from Time Machine (which was done from Leopard).

    Everything worked without a hitch except for a constant spin-up / spin-down effect that sounded like the new HD was trying to spin down every 15 seconds or so. It would cause my computer to freeze momentarily and became very annoying. It turns out some Mac laptops have issues with the power management configuration of non-standard hard drives. I searched around a bit and found a utility called hdapm, which eliminated the problem instantly. All has been running just fine since then.

    If you have a similar issue, you can snag the utility here:

  • Well unfortunately I won’t be buying an MLC SSD anytime soon until Stevo bring TRIM support into OS X.

  • Please also consider a 7200 rpm HD will make your MacBook get hotter and, more importantly, shorten battery life.

    I recently upgraded my Mac’s HD with a bigger, faster 7200 rpm and I wish I had taken that into account, my battery drains now quite much faster to the point it makes my HD speed gain not really worth it due to a shorter battery duration :(

    When upgrading, I would stick to a 5400 rmp HD unless you really want to sacrifice battery life for HD access speed.

    • Interesting observation, I never considered battery life!

  • I did this recently on my 2 day old mac book pro, as i only bought the cheapest 13″ i was quite surprised by the instructions from apple even in the back of the little book it came with, showing me where the long screws go and how to do it.

    From a 250gb Momentus Seagate drive to the same model 500gb drive. Its made such a difference even from a new machine. And no compromise to battery life so it would seem. I saved myself a lot of money doing it myself as supposed to the apple store upgrade from new.

    Great posts, as always from you guys, they have helped me out so much from being a PC user for so many years.

    • Glad you’re enjoying them, Martay. Thanks for the kind words.

  • If you plug in a new internal hard drive, do you need to install the Mac OS first, or can a Time Machine backup on an External hard drive do the trick?

    • Yes, can anyone comment? The mechanical replacement of a hard drive is the part I fully understand. Repopulating off of my time machine backup ? How does that work? Can migration assistant work if I am not transferring from one computer to another? If my optical drive is shot too because it is so old, what can I do?

  • Great article.
    This week I upgraded my aged MBP internal drive to a brand spanking new one from One Word. Their online videos (on YouTube) walked you through the process but I still managed to bend a few things I shouldn’t have…. I purchased their replacement packet which had a metal enclosure to turn my old drive into an external USB drive. Pretty slick.

    One thing I would recommend is to run CarbonCopy Cloner on the new drive (in the enclosure they provide). When I swapped out the drives, my system and apps were in their new roomy home and I was back to work within an hour.

  • So a SSD consumes less power and generate less temperature?

  • Awesome article! Thanks!

  • Upgrading Mac hard drive is not an easy job one has to be very knowledgeable about the Mac system it could be some data loss disaster when upgrading the hard drive of your Mac system.Or you must keep your backup of your data otherwise data could be lost during any circumstances or you can use some data recovery tool if had fall into the data loss situation like Stellar Phoenix Macintosh Data Recovery which is versy easy to use and have many data recovery options and features.You can try the free trial version of this software first if successful then go for the full download otherwise not…