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View Full Version : Troubleshooting: Losing Your Memory



MTBlogBot2000
23rd August 2010, 12:53 PM
<img class="alignright size-full wp-image-9322" title="mac_ram14" src="http://www.mactalk.com.au/wp-content/uploads/2010/08/mac_ram14.jpg" alt="" width="300" height="203" />Every computer needs memory, or RAM, to function. Without RAM installed in your Mac it won’t even be able to boot.

As with any other problem you experience with your computer, the first thing to do when you’ve got problems is to figure out what’s wrong. Once you’ve done that, the hard work is over. All you have to do then is fix it. Almost always, fixing a fault is the easiest part of the repair process.

The key to identifying a fault is understanding and matching symptoms to their likely causes.
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<h2>Failure Symptoms</h2>
In common with most computer hardware faults, you <strong>can’t</strong> afford to ignore it. <strong>No</strong> hardware fault gets better on it’s own. They <strong>all</strong> get worse over time.

Symptoms of a minor RAM failure:
<ul>
<li>Applications crash, not always the same application and not always when doing the same thing.</li>
<li>OS X becomes unstable and things that would normally work fine have problems.</li>
<li>Problems get worse the longer you use your computer.</li>
<li>Problems get worse the more programs you run and the harder you work your computer.</li>
</ul>
There’s really only one significant symptom of a major RAM failure - your computer will power up but won’t actually boot. Depending on the severity of the failure, you may not even get anything on the screen and the only way you’ll know your computer powered up at all is by listening for a fan or by a power LED being on.
<h2>Treatment</h2>
The good news is that RAM doesn’t store any critical data. When your RAM fails, it doesn’t, as a direct result of that failure, destroy the data stored on your computer.

The bad news is that you don’t repair RAM. Your only choice is to replace it.

While this makes a RAM fault a relatively simple fix on a computer, don’t ignore it.

Any time an application crashes, the data you’re working with in that application can become corrupted. The more often something crashes, the more chance there is that damage will be done. What can happen for applications, can also happen for OS X itself. String enough crashes together and you may end up with a very sick Mac indeed.

The moral here, that bears repeating, is that you <strong>never</strong> ignore hardware faults. They <strong>always</strong> get worse.
<h2>Recovery</h2>
For most models of Apple computer, RAM is a user replaceable part. This means you can install, or replace, RAM in your computer without voiding the warranty. Because of this, in many Apple computers, replacing RAM is one of the easiest jobs you can do.

In order to replace the RAM in your Mac you’ll need to gather some information about it first.
<ol>
<li>Find out what RAM type and configuration of RAM is used in your Mac.</li>
<li>Find out how to replace the RAM in your Mac.</li>
<li>Find, and buy, compatible RAM for your Mac.</li>
</ol>
The first two steps can be fairly neatly handled by finding the user guide for your Mac. If you can’t find the printed copy that was included with your new Mac then they’re also available online. In order to get the right user guide, you have to know what model Mac you have.

Grab the serial number for your Mac. If your Mac still boots, this is pretty easy. Head on up to the Apple menu at the top left of your screen and select “About This Mac”.
<p style="text-align: center;"><a href="http://www.mactalk.com.au/wp-content/uploads/2010/08/Menu-AboutThisMac.png"><img class="size-full wp-image-8822 aligncenter" src="http://www.mactalk.com.au/wp-content/uploads/2010/08/Menu-AboutThisMac.png" alt="" width="265" height="299" /></a></p>
This will bring up a window that shows you some basic information about your Mac. It isn’t enough for our purposes though, so go ahead and click on “More Info...”.
<p style="text-align: center;"><a href="http://www.mactalk.com.au/wp-content/uploads/2010/08/AboutThisMac.png"><img class="size-medium wp-image-8823 aligncenter" src="http://www.mactalk.com.au/wp-content/uploads/2010/08/AboutThisMac-243x300.png" alt="" width="243" height="300" /></a></p>
This will start System Profiler and bring up a new window that can list a wealth of information about your Mac. To start with, we’re interested in the model identifier or the serial number of your Mac. These are both visible when System Profiler first loads.
<p style="text-align: center;"><a href="http://www.mactalk.com.au/wp-content/uploads/2010/08/SystemProfiler-Model_Serial.png"><img class="size-full wp-image-8824 aligncenter" src="http://www.mactalk.com.au/wp-content/uploads/2010/08/SystemProfiler-Model_Serial.png" alt="" width="526" height="367" /></a></p>
If your Mac doesn’t boot anymore, go to Google and do a search for “how to find serial number on (insert the model of your Mac here)”. This should get you a match on Apple’s support website that gives you instructions to get your serial number.

Once you have the serial number, you can use this information to get the exact model of your Mac by going to <a href="http://www.apple.com/support/">http://www.apple.com/support/</a> and clicking on the “Check Your Service and Support Coverage” then entering the serial number. This will tell you exactly what model Mac you have. You can the model information to then work out what model identifier is applicable (Wikipedia - <a href="http://en.wikipedia.org/wiki/Apple_Inc.#Mac_and_accessories">http://en.wikipedia.org/wiki/Apple_Inc.#Mac_and_accessories</a> - has a good list of models together with their identifiers).

In reality, most of the time you only need the model identifier to get a user guide so don’t worry about doing the serial number stuff unless your computer doesn’t boot.

On Google, do a search for “user guide for MacBook Pro5,4” (use your own model identifier instead of the one shown above) (of course, if you’ve got a MacBook Pro5,4 then feel free to use this search...).

This will almost certainly get you a match on Apple’s website where you can download a PDF version of your user guide. If it doesn’t, do the same search from<a href="http://www.apple.com/support/"> http://www.apple.com/support/</a> and you should find exactly what you’re looking for.

The user guide will give you details about the RAM in your computer. Look in the index for something about adding memory to your computer. What you should find is details on the specifications of the RAM you’ll need and how to access that RAM. Often, this will involve removing a panel or door that’s held in place by some screws.

If the user guide isn’t clear enough, try looking for help from <a href="http://www.ifixit.com">www.ifixit.com</a> - they have some great illustrated manuals that’ll help you work it all out.

All you need now is to find the right RAM. There’s plenty of ways to do this, but lets stick with a MacTalk sponsor and go to <a href="http://www.ramcity.com.au">www.ramcity.com.au</a>. Click on Apple and then on the model identifier for your Mac. This will give you a list of compatible RAM for your Mac as well as some brief details on things like the maximum RAM you can use and the number of RAM slots available. Buy your RAM and you’re good to go.
<h2>Action Plan</h2>
To save yourself some hassles later, why not record your model identifier and serial number somewhere safe? Keep a notepad of important information handy and include this stuff. That way, you won’t have to jump through as many hoops if something goes wrong and you can’t boot your computer.

While we’re on the subject of RAM, upgrading can offer significant performance increases for comparatively low cost. It’s worth checking the maximum RAM capacity of your Mac and seeing if it’s worth doing an upgrade. Almost everyone will get at least some benefit from increasing installed RAM on their Mac.

<address><em>David Freeman is an Apple Certified Macintosh Technician and the proprietor of <a href="http://www.outbackqld.net.au/">Outback Queensland Internet</a></em><em> (aka Leading Edge Computers Longreach). He has worked as a technician for over fifteen years and been involved in computers and the Internet since 1988 when he purchased his first computer (an Amiga 1000).</em></address>

dbolli
24th August 2010, 08:36 AM
Whilst I agree with most of the points mentioned, I think the article gives the impression that faulty RAM is the only reason for Apps and OS X crashing and otherwise misbehaving. I think it's worth mentioning the need to run RAM tests using something like TechTools Pro (Micromat - Home (http://www.micromat.com/)) to eliminate faulty RAM as a cause. I'm sure there are equivalent freeware or shareware utils available but I like TechTools Pro.

glacierdave
24th August 2010, 12:03 PM
The unfortunately reality of computer problems is that, in the early stages at least, there's a heap of overlap between various fault types. Of course faulty RAM isn't the only reason apps will crash. Only further diagnostic testing is going to determine if instability is because of faulty RAM, a faulty hard drive, overheating, low quality mains power, or any number of other causes.

TechTools Pro is a good choice for testing RAM. If you've purchased AppleCare (and you purchased with the disc) then you've also got a version of this software and can use it to assist in diagnosing RAM (and other) faults.