Problems upgrading RAM of early 2008 iMac

Discussion in 'iMac' started by IvarO, Jan 6, 2015.

  1. IvarO macrumors newbie

    Jul 25, 2014
    Hi, here's one for all you tech experts:

    I have an older iMac, early 2008, that I'm trying to squeeze for its last drops of life. I'm planning on installing an SSD, but first, I'm maxing out the RAM. I already have 4GB, the official max, but all over the net there are reports of people having success with 6GB (4 + 2).

    The RAM already in the machine is two Crucial 2GB sticks: CT25664AC800: DDR2 PC2-6400 • CL=6 • Unbuffered • NON-ECC • DDR2-800 • 1.8V • 256Meg x 64.

    My new stick is also Crucial, 4GB, bought it from a fellow who bought an 8GB kit but realized he could only use one of them in his identical machine. Apparently he had success. Specs: CT51264AC800: DDR2 PC2-6400 • CL=6 • Unbuffered • NON-ECC • DDR2-800 • 1.8V • 512Meg x 64.

    So except from the 256Meg x 64 and 512Meg x 64, they seem identical. I've never had problems with Crucial hardware before, and the other matched stick in the pair works it this other guys iMac.

    I've tried the 4GB stick alone in both the left and right bank, and also in both positions with a 2GB stick in the other one. All I get is a black screen, and series of three beeps that repeat infinitely (- I assume, I can only bear the sound for a minute or two.) I can hear the CD drive spinning up, otherwise nothing is happening. Back to 2 + 2 GB sticks, all is fine.

    Does anyone have a clue? Bad stick, or something that can be worked out?

    Is it worth the hassle going from 4 to 6 GB? I'm running Yosemite on it, it's not exactly speeding along, but it works.

    Fire away, geniuses!
  2. GGJstudios macrumors Westmere


    May 16, 2008
    If the 4GB stick was properly seated and you didn't have success in either slot, it sounds like it may be a defective module. Your iMac will definitely support 6GB, with a 2GB and a 4GB module.
  3. IvarO thread starter macrumors newbie

    Jul 25, 2014
    Thank you for quick reply!

    The modules all clicked firmly in place, and I've tried all possible combinations, so I guess you're right.
  4. Brian33 macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    For what it's worth, I concur with GGJstudios. I have a 24" Early 2008 iMac, 2.8 Ghz Core2Duo. I've been using 6 GB (one 2 GB and on 4 GB stick) successfully for quite some time. I haven't looked up the exact part number you gave, but the specs look right. My 4 GB happens to be Patriot PSD24G8002S 4GB PC2-6400 800MHz CL6 SoDimm, according to the package.

    Whether it's worth going from 4 GB to 6 GB is hard to say. I can't say I monitor it all that closely, but I believe I usually have 2 or 3 GB of memory free, running 10.8.5 Mountain Lion (iTunes, Mail, fairly light Firefox use, Terminal, Plex Media Server all running). However, I occasionally run an XP or an OS X virtual machine using VirtualBox (which works wonderfully, by the way!) and then I'm really glad to have the 6 GB RAM.

    By the way, if you're interested in putting an SSD into your iMac, I can recommend it! I put in an SSD, replaced the optical drive with a 2.5" 1 TB HDD, and configured a DIY Fusion drive. I'm very pleased with the result. I hope I'm not naive in hoping to get another couple of years or more out of this machine! It does a great job at everyday tasks, and in my opinion, still does reasonably well at processor-intensive tasks like transcoding video, joining many audiobook chapters into a single audiobook, minecraft server, ripping DVDs, and iMovie editing, to name some of the tasks I've been doing with it.
  5. IvarO, Jan 11, 2015
    Last edited: Jan 11, 2015

    IvarO thread starter macrumors newbie

    Jul 25, 2014
    Thank you for this input. As a matter of fact, I have just done so, after doing it with great success with my MacBook Pro 2009 a year ago. The effect was really amazing. This time, I went down the quickest, but obviosly not the best route. I swapped the internal 1 TB HDD with a 250 GB SSD, attached a FW 800 WD MyBook (or something) that I had lying around, and made a fusion drive out of them. I then installed OSX Yosemite from scratch, and transferred my user account from a fresh Time Machine backup. Initially it worked well, but today the system just froze, and now I only get a very forbidding "no entrance" sign when I start the iMac. I think this could succeed with another external hard drive, I really don't trust these external WD drives, they have too "smart" firmware and need proprietary software to be formatted and configured "the right way". I tried to swap the disk in the WD enclosure with a faster, more quiet 2 TB disk, but that was a no go, the WD firmware refuses do work with non-WD disks. I could swap the DVD drive with a hard drive enclosure, but I need to think long and hard about it first.

    I have tried running the MacBook in Target mode and starting the iMac from that through FW 800, and that works well, except the MacBook seems to work surprisingly hard for what is in effect en external drive enclosure, and after a while the fans are on max RPM.

    It is very tempting to rob a bank and then buy new hardware. To keep me going until I the next-gen iMac and/or the 12" MacBook materializes, I will try a non-fusion setup with OSX, apps and some data on the SSD, the rest on an external drive. I give up on the memory issue.

    Luckily, I have learned my lesson long ago, so I have redundant backups both on- and offsite. No data was harmed in this experiment!

    Edit: Actually, I solved the "no entrance" sign, the reason was the stupid WD drive. I turned everything off, unplugged the drive, and plugged it back in *after* i had turned on the iMac. It then whirred to life, and was online in time for when the iMac started reading data from it. I think it needs both power and some activity through its connection to the computer to turn on. As I said, too smart for its own good. It goes in the bin as soon as I have a replacement, and time to reconfigure the iMac.

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