8 Replies Latest reply: Dec 16, 2006 12:31 AM by Dave Morgan
Dave Morgan Level 2 Level 2 (170 points)
Hi

When I bought my iMac G5 I specified 512meg of RAM. I recently added another 1gig giving a total now of 1.5gig.

I make good use of Adobe Photoshop and Bridge, Safari, Pages and iWeb.

Since adding more RAM the machine has felt more 'solid' but it would be hard to say I have noticed a real jump in speed.

Is it worth adding more RAM? If so how much will make a noticable difference?

Thanks in advance for any advice on this.

David

iMac G5, Mac OS X (10.4.8), 1.5G RAM iSight Bluetooth KeyBoard & Mouse
  • jmaa Level 1 Level 1 (15 points)
    David, If your iMac is rev A, and only then:

    Because of the system architechture tere is a boost when you use two identical DIMMs in your memory banks. I wouldnt be surprised if your rev A iMac would feel faster with two identical 512 MB DIMMs (making total 1 GB) than your current configuration of 1.5 GB RAM with non-identical DIMMs.

    But since your talking about Pages and iWeb I doubt this is the case (those werent out yet when they sold rev A iMac G5s) and youve got rev B or C, in which the system bus was redesigned and this "128-bit memory bandwidth only with two identical DIMMs, otherwise 64-bit" problem was solved.
  • Eric Kracinski Level 6 Level 6 (15,925 points)
    There really wouldn't be much of a difference from 1.5 to 2GB of RAM unless you have a large number of pageouts. Those pageouts can be an indicator that your RAM needs are greater than what your system has.

    The Adobe apps you are running are system hogs and will not be quick no matter how much RAM you have.

    That said, you should see a difference with the addition memory. Is the system recognizing it in the system profiler? If so, maybe take a few minutes to run Memtest found HERE. The new module may not be working properly.

    Also, be sure that all your apps and the OS are completely up to date.
  • Dave Morgan Level 2 Level 2 (170 points)
    Hi there. Thanks for the reply. How do I tell whether I have a rev A machine or not?
  • Dave Morgan Level 2 Level 2 (170 points)
    really wouldn't be much of a difference from 1.5 to
    2GB of RAM unless you have a large number of
    pageouts.


    How do I find out how many pageouts I have. By the way what are these? - Use of the hard disk instead of RAM?

    That said, you should see a difference with the
    addition memory.


    How much do you think I would have to add to see a recognisable uplift in performance from 1.5 gig?

    Is the system recognizing it in the system profiler?


    Yes it is.


    Also, be sure that all your apps and the OS are
    completely up to date.


    They are up to date.



    Thanks

    David
  • Eric Kracinski Level 6 Level 6 (15,925 points)
    The specs for all iMacs can be found HERE. If your machine shipped with Panther (10.3) then it is a first gen G5 iMac. If that iSight is a built-in iSight and you have a G5, then you have the iMac iSight model.

    Pageouts can be found in your activity monitor. Open it up and hit the "system memory" option. Next to the pie chart is an entry for "page ins/outs." Pageouts are cumulative since your last restart, so if there are a large number of pageouts, that in itself is not an indicator that you need more RAM. If the number of ins is close to or larger than the number of outs, then you need more RAM.

    Right now, my Mac has been on for over 4 days and I have 69611 page ins and only 1164 pageouts.

    When I said you should see an increase in performance, I meant from the 512MG to 1.5GB, not from 1.5GB to 2GB. If pageouts are not a problem, it would not matter if you had more RAM since your system is not fully utilizing what it already has.
  • Dave Morgan Level 2 Level 2 (170 points)
    If your machine shipped with Panther (10.3) then it is a first gen G5 iMac. If
    that iSight is a built-in iSight and you have a G5, then you have the iMac
    iSight model.


    Yep it shipped with Panther about 18 months ago. I don't have a built in iSight camera.

    If the number of ins is close to or larger than the number of outs,
    then you need more RAM.


    Currently this shows Page ins 100932 and Page outs 73592. The Mac has been on for a few hours.

    What conclusions would you draw from this? Replace the 512 with a 1gig as this would lead to an improvement because there are more Page ins than outs and also because the Mac is rev A that the internal design benefits from two DIMMS of the same size?
  • jmaa Level 1 Level 1 (15 points)
    I think the safest way to say what rev your iMac is, is for you to think when exactly was it that you bought your iMac.

    Rev A
    Introduction Date: August 31, 2004
    Discontinued Date: May 3, 2005

    While it's not impossible to have been sold rev A iMac after May 3 2005, it's unlikely. If you bought your iMac later than May 3rd, I'm pretty sure it's rev B. If you bought your iMac before that, it's rev A and theres no question about it.
  • Dave Morgan Level 2 Level 2 (170 points)
    I think the safest way to say what rev your iMac is, is for you to think when exactly was it that you bought your iMac.


    I had a think about this some more and I concluded that what was important was when the thing was manufactured rather than when I bought it. So, did some more digging on the boards and came across this link -

    http://www.chipmunk.nl/klantenservice/applemodel.html

    I am now sure that I have a Rev A iMac. I have ordered another gig of memory and am looking forward to the increase in speed due to the fact that both DIMMs will be the same size. Hopefully.

    TVM

    David