Sunday, June 24, 2012

Does my iMac need more memory?

Activity Monitor
Activity Monitor (Photo credit: Wikipedia)

The Problem

I had my previous iMac for about 5 years.  It kept running slower (and slower and slower).  It went from being a screaming, stable platform that I loved to work on to something almost almost as bad as my Windows machine with the spinning beach balls all the time.  I had maxed it out on RAM, 4 GB.  So, I decided it was time for an upgrade, trotted down to the Apple Store and plopped down my money for a 27" iMac with a 2.7 GHS Intel Core i5 processor.  I asked the Apple salesperson about additional RAM and she asked me what applications I was running.  Just the normal stuff, a couple of browser windows, iTunes so I could whistle while I work, iPhoto on occasion, MS Word, Powerpoint, etc.  She said that 4 GB of RAM would be more than sufficient for me because none of the applications I was using would take advantage of more memory. Boy was she wrong!  Yesterday, I upgraded to 12 GB of RAM and I immediately fell in love with my iMac again. It's the best $50 I've ever spent on computer hardware Here's how to tell whether or not you need to upgrade too.

After months and months of going through this experience I realized something.  The beach ball was popping up, not when I was within an application but when I was switching or launching a new application.  If I were working in iPhoto for example, it would run fine.  But, when I tried to switch over to check my mail or take an order from a customer over the phone in Safari, the beach ball would stop me dead in my tracks.  After getting the new machine, I made the mistake of buying MacKeeper reasoning that I had legacy software on my system from my first iMac bought almost 10 years ago and maybe all that stuff was clogging my system up.  That's a story for another day.  Just don't do that.  I finally ran across some articles that showed me how to scientifically determine if I needed more memory.  After just a few minutes, it became VERY clear that I did.

How to Know If You Need More Memory

What you'll want to do is go to the Utilities folder and open Activity Monitor.  In Activity Monitor, there is a tab called System Memory. This will show you exactly what is going on with your memory on your Mac.  You might want to do a restart before you try this to reset Activity Monitor.  Open it up first with no other applications running. You'll see the processes you have running the percent CPU they're using and the amount of real memory they're using. But, what you really want to look at is at the bottom of this window.  On the left, you'll see Free, Wired, Active, Inactive and (Total) Used memory.  With no other applications launched, you should see a fair amount of Free Memory (Green on the pie chart to the right).  Wired and Active Memory should be relatively low and Used should be a fraction of your total memory.  As you perform activities on your computer, the RAM gets allocated and used by applications.  The operating system pages out to your hard drive when it runs out of space in your physical RAM.  This page out (represented in the right hand column) can severely slow down your computer.  The total amount of space allocated for paging in and out is Swap used.  You'll want to keep an eye on the Page Out and Swap used numbers in particular.  They should be relatively low.  Before I made my memory upgrade, Swap used was actually approaching 4 GB at times and the Page outs were in the multi-GB range also.  Free memory would often dip to just 30-40-50 MB and this is when the beach ball would pop up.

With Activity Monitor open, start to open up applications and go about what you would normally do while working. Here's where the salesperson at the Apple store was wrong.  She was right that none of my applications are true memory hogs. I don't work with very large files or do a lot of hardcore video editing.  But, because I work from home, I'm on my computer all day and I don't shut down on thing when I move to the next.  I typically have at least iTunes, Mail, iCal, Safari (with 5-10 tabs) open.  And, it's nothing for me to launch iMovie and/or Excel while all of these other things are still open.  As long as I was working within an application, everything would be fine.  But, if the phone rang while I was creating a video and I switched over to take an order, my machine would lock up, just when I needed it most.

So, after just a few minutes of this testing I knew, beyond the shadow of a doubt that a memory upgrade would help me.  I read that the amount of Swap used would give me an indication of how much more memory I needed.  In my case, the Swap used would max out around 4 GB.  If you've bought memory, you know that while it's a LOT cheaper than it used to be, the dense DIMMS are still relatively expensive.  So, the decision I had to make was how to utilize the two open slots Apple had left me.  In the previous iMacs, you only had two memory slots. So, any memory upgrade meant throwing out what you had already paid Apple for.  But, the new iMacs have (4) slots and ship with (2) 2 GB DIMMS.  I decided to keep those and add (2) 4 GB DIMMS taking me up to a total of 12 GB.  The guy at, where I bought the memory, tried to convince me that I might want to go to 20 GB.  But, adding 8 GB DIMMS was going to be about three times the just twice the total amount of memory. Having looked at Activity Monitor, I was pretty sure that 12 GB would be more than I need.  Better to save the money, add just what I need for now and upgrade later, if I need to.

I installed the additional 8 GB yesterday.  As you can see from my screenshot above, now with all my normal applications open, I still have almost 7 GB free (almost twice the total amount of RAM Apple shipped my iMac with).  This now truly feels like a new machine.  Application switching is now smooth and seamless the way it should be.  And this only cost me $50 and took about 5 minutes to install.
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