Memory Issue - Strange One

chrislad

I got 2 * 2gb DDR sticks for my iMac today from crucial.com. I used their system scanner as the maximum my iMac could take was 4gb. It's not the newest version of the iMac that was released a couple of weeks ago, but the one just before it.

There was 1gb of RAM in it. 2 slots for RAM. 1 * 1gb stick with the machine.

So, I got my sticks today, installed them, turned on my iMac and.... nothing. Just whirring and some soft fan noises. I removed both memory sticks, put back in the old one and it was working. Odd, I thought. Must not have put them in right the first time. Tried again. Screen blank etc. Next time I removed one of the 2gig sticks, put in the old 1gig stick, and it started up without issue - 3gb RAM in About My Mac. Dodgy stick then? Nope. Swapped the 2gig sticks around and the same thing - turned on with 3gb of RAM.

I'm perplexed. Both sticks seem to be working, just not together. Is this an iMac issue or something wrong with the memory? Any help appreciated.

aidan_walsh

Are you certain you haven't put in the 1GB stick by mistake? How old is your iMac? What version of OS X are you using?

chrislad

iMac is about 4 weeks old. Using the latest version of Leopard.

I have the 1gig in now, as the machine will only boot with the combination of 1 * 1gig and 1 * 2gig and will not boot if I have 2 * 2gb.

aidan_walsh

Ah, I follow now.

Getting any tones like these?

Try resetting the NVRAM or running a Hardware Test with both sticks installed (required startup key combinations are here).

chrislad

No tones when I start up at all. Just the slight whirr of the fans. Will try the reset and report back.

Simon201

Could be they've sent you 800MHz memory instead of 667MHz and it's starting up just using your original 1gb stick?

chrislad

I've checked the memory that's in the iMac at the moment. Both are 667MHz (that's the 1gig and one of the 2gigs).

I don't think that one of the 2gigs is 800Mhz, for the simple reason that both 2gigs booted with the iMac when the 1gig was inserted.

Do I have to have both 2gig sticks in to reset the NVRAM or can I do it as things stand now?

ZENER

Hi Chrislad, congrats on the new Mac ! Firstly did you buy it in the Apple online store or in a shop like PCWorld ?

Do this:

Click Apple at top left of screen > About This Mac. You get this:



Now click the "More info . . ." button: You get something resembling this:



This is the hardware overview page, beside the entry Bus Speed: in the right hand pane do you see 800MHz or 667MHz ?

You say the old RAM is 667MHz in your posts, if this is the case then your Mac is older than you think. The 800MHz bus means the newer Intel chipset which addresses correctly above 3.2GB of RAM and will indeed take the full 4GB you bought. If it's the older 667MHz bus then the limit is 3GB.

ZEN

chrislad

The model is iMac 7,1. Bus speed is showing up as 800Mhz.

Got the iMac in PC World for 900e. It was one of the just about to be discontinued models. 320gig HD, 2.4Ghz C2D, 20'' screen.

Sad Professor

From my own experience just because the machine is starting up and the RAM is being recognised doesn't mean there isn't a bad chip. I'd recommend downloading Rember/Memtest from here and test it with different combinations of RAM to see if everything is ok. And although it's unlikely you should also consider the possibility that there's a bad slot so keep note of which slot each chip was in when you tested it.

Also are you definitely inserting the chips correctly? You should hear a click sound.

chrislad

I did 3 years of Computer Systems in UL, so I know a thing or two about computers

Did the memory test on the current set I have in the machine, with the following results.

Test Results

All tests passed!

Total built-in memory: 3 GB


This is the total amount of physical memory that the computer has installed. If this figure is not showing the correct amount of memory there may be a problem with one or more installed DIMMS.

Available memory: 2696 MB

Available memory is the amount of physical memory that is currently not in use by any other processes. All available memory will be used for testing when the "All" option is selected. To increase the amount of available memory, you can restart your computer before testing. If you are familiar with the command line (CLI), you can run memtest (the core of Rember) in single-user mode. See Rember help, or http://www.memtestosx.org for more information.

Requested amount: All MB

The total amount of memory requested for testing by the Rember application. Not all requested memory can be allocated for testing. See information on "Available memory" for more information.

Memory allocated for testing: 2621 MB

This is the total amount of memory that memtest was able to allocate for testing. See "Available memory" section for more information.

---

Loops selected: 1

Total loops selected by user for testing. All loops should complete when testing is successful. Test failure when the "Continue on Error" preference is selected will cancel tests before this number of loops has been completed. Users can also cancel testing before this number is reached.

Loops completed: 1

Total loops completed by memtest. Note that the Rember is not always able to identify how many loops ran. If there are discrepancies between this and the loops selected, the log should be examined to determine exactly how many loops were performed.

---

Total execution time: 2618 seconds

This is the total amount of time that it took to execute the selected tests. Execution time may vary from system to system, and is provided as a guide for determining how long users can expect tests to run based on the amount of memory installed on the system.

Testing start time: 2008-08-07 21:00:23 +0100

Testing end time: 2008-08-07 21:44:03 +0100

Will try the other set tomorrow when I'm off.

muggyog

Go with Zeners' advice on this.
There are two iMac7,1s'. The X7900 chip and the Q6600 chip versions (note X7900 bus speed is 800Mhz but the RAM speed is 667Mhz).

chrislad

muggyog wrote: »

Go with Zeners' advice on this.
There are two iMac7,1s'. The X7900 chip and the Q6600 chip versions (note X7900 bus speed is 800Mhz but the RAM speed is 667Mhz).

Here's my system specs. Hope that helps.

ZENER

OK I've doubted myself on this for the past day or 2 so I did some checking. New 4GB Macs have a 1066MHz bus and take 800MHz memory. 800MHz bus Macs take 667MHz RAm like yours.

According to this chart your iMac should take 4GB of RAM if it's a Rev C. C2D Mac with the new Aluminium and Black design.

The speed of the RAM isn't important here provided it's above 667MHz but there are other parameters in RAM make up as I'm sure you're aware that might have an effect - CAS Latency (CL) etc.

When you have the 3GB combination installed have you tried starting up a lot of apps so that the real memory is consumed ? Try doing some work in these apps and push it to the limit. Do you get KPs ?

There might be some small discrepancy in the modules. To be honest I thought the change to Intel chipsets and CPUs would do away with all these problems which used to plague Mac users in the PPC days.

ZEN

muggyog

Zener youve just reverse biased yourself

I believe you were correct first time regarding the 3Gb limit. From http://en.wikipedia.org/wiki/Intel_Core_2, I've captured what I believe is the relevant info (see enclosed pic).

Look for X7n00 and Q6n00.

babypink

in the diagnostics option in the system profiler, check to see if there is an error reported at the Power On Self Test.

normally it should just say passed, but if there is an error is might well show up there.

I would also run the AHT as aidan suggested above. Its better than memtest as it examines ALL memory and ALL hardware, not just 90ish% of it....it'll also highlight whether there have been any POST errors.

There may well be a latent hardware issue going on here.

chrislad

Power On Self Test

Last Run: 07.08.2008 22.07
Result: Passed

Will try the AHT now.

chrislad

Right. Ran the Rember on the combination of both 1 and 2 gig combinations. I tried (again) switching the memory around different slots, and no luck. I then ran the AHT and everything came up fine. No errors found, and I did the full test, which took about 80 minutes.

I'm stumped.

Sad Professor

A few people over at the Apple Discussions with a similar problem, no solution though.

http://discussions.apple.com/thread.jspa?messageID=7769442&#7769442
http://discussions.apple.com/thread.jspa?messageID=7232195&#7232195
http://discussions.apple.com/thread.jspa?messageID=7602163&#7602163

chrislad

Meh, guess I'll just contact Crucial and see what they can do. Thanks for the help, guys.

ZENER

muggyog wrote: »

Zener youve just reverse biased yourself

If I was reverse biased then I'd be switched off to everything and unwilling to admit I was wrong which it appears I was !!

I believe you were correct first time regarding the 3Gb limit. From http://en.wikipedia.org/wiki/Intel_Core_2, I've captured what I believe is the relevant info (see enclosed pic).

Look for X7n00 and Q6n00.

I saw that chart too but as far as I know it's not the cpu that decides the memory addressing it's the other glue chips surrounding it. The C2D chips are 64bit. I have a C2D chip in a Intel mainboard (Gigabyte DS3L)and manage 8GB RAM with it because it's the latest chipset. The glue chips contain the memory CAS & RAS and addressing system and it's these that limited the memory to 3GB in earlier models.

While they could address 4GB memory space, the upper part of this was used to address peripherals, drives and AGP memory I think thus limiting the physical RAM that was addressable to something like 3.2 GB.

Now I recall that it was technically possible to actually install 4GB physical RAM in the machine but the machines ignored the stuff above 3.2GB. I believe that some machines KP'd when actual RAM usage went into the forbidden zone but I think it was more likely that it just got ignored.

None of these of course apply to chrislad's situation which might just be down to wrong memory type.

Edit:
Chrislad says his iMac is only a few weeks old. According to Apple all iMacs since April support 4GB. Confusingly though it says that these iMacs come with 1GB of 800MHz RAM installed

Somebody some where is telling porkies !! Chrislad says his iMac has 1GB of 667MHz RAM which makes it older than April according to Apples site ?!

Can you give us the exact model number from the hardware profiler or the label on the iMac. It will be something like MB324LL/A which is a 20" iMac with 2GB 800MHz RAM. This might help clear this up once and for all !

ZEN

chrislad

I purchased the iMac about 4 weeks ago. Going from the Apple.com site, support ends on 28th Oct 2008, which means it's been sitting in PC World since probably Christmas 2007 or so, hence why it doesn't have the 800Mhz RAM. I only got it a month ago, but it had been sitting there a bit. I did say it was the last of the last line of iMacs before the update about 6 weeks ago.

J-blk

Removed - the 2.4Ghz variation would have to be one of the aluminum ones right? There have only been two revisions so far and all the specs do point that they should support up to 4GB... weird.

Simon201

chrislad wrote: »

support ends on 28th Oct 2008

I think you'll find that ordinary Applecare support ends a year from your purchase date - four weeks ago? If it says 28 Oct 2008 on the Apple support site, you can get it changed if you supply confirmation of the receipt from PC World, although god only knows why PC world have it sold on 28 Oct 2008. Ironically I had exactly the same issue when I bought an eMac from PC world 3 or 4 years ago. When I went to register it, the Apple support site said it had been purchased and registered a few months previous!
Anyhow I'd like hear the outcome of this issue Chrislad cos I'd like to get another 2gb for my own (exact same) iMac.

chrislad

Oh, I know the support ends from purchase, of which I have my receipt so there's no issue there. PC World were fairly good to be honest, with exchanges. My Apple TV, which I got in Dec 2007 from them, died in May. Brought it back, expecting them to repair it, and they just gave me a new one.

Changing it on the Apple site is a pain. They require you to fax them the receipt. Is this the 90s? Who the hell has a fax machine anymore? Emailing it to them isn't sufficent.

The 28 Oct date is the date Apple first logged the serial number of the Mac.

It is one of the Aluminium ones, definitely.

whiterebel

chrislad wrote: »

Oh, I know the support ends from purchase, of which I have my receipt so there's no issue there. PC World were fairly good to be honest, with exchanges. My Apple TV, which I got in Dec 2007 from them, died in May. Brought it back, expecting them to repair it, and they just gave me a new one.

Changing it on the Apple site is a pain. They require you to fax them the receipt. Is this the 90s? Who the hell has a fax machine anymore? Emailing it to them isn't sufficent.

The 28 Oct date is the date Apple first logged the serial number of the Mac.

It is one of the Aluminium ones, definitely.

That usually means its an ex-demo if PC World have a purchase date entered on Apple's system. If I were you, I'd get it sorted now, before you are stuck and faffing around looking to get the receipt faxed etc, in the future. Apple won't help until the purchase date from PC World is corrected on the system. If PC World had it up as a demo, Apple won't usually repair them anyway, once the 12 months has gone.

chrislad

It's not a demo unit. I unsealed the box myself and it was all new. I can change the date on the site any time within the next 48 weeks anyways so I'm covered. My AppleTV is the same. Purchase date doesn't match receipt date on the site.

ZENER

Hi chrislad, any luck finding the model number ? It'd help figure this one out.

ZEN

chrislad

Yup, the model number on the sticker at the base is A1224.

ZENER

Is there another number - The Marketing Number - beside that beginning with MAxxxx/xx ? The number you've provided doesn't mean anything.

On Apples' support site it gives the last 2 revisions of the aluminium iMac and their specifications. From that it's upgradable to 4GB.

ZEN

chrislad

ZENER wrote: »

Is there another number - The Marketing Number - beside that beginning with MAxxxx/xx ? The number you've provided doesn't mean anything.

On Apples' support site it gives the last 2 revisions of the aluminium iMac and their specifications. From that it's upgradable to 4GB.

ZEN

There's nothing like that on the machine itself, but I do see that on the box as a Part No. It's MA877B/A

Simon201

chrislad wrote: »

The 28 Oct date is the date Apple first logged the serial number of the Mac.

I'm rather curious about what you're saying there, like the only person to 'register' (if that's what you mean) the machine after purchasing is going to be the purchaser - i.e. you (and not Apple) - after it's been purchased. Surely the serial number should not be 'logged' at all until you did it yourself?
There certainly seems to be some strange goings on in PC world if your Apple TV thing has the same purchase/warranty discrepancies!

chrislad

The exact wording on the Apple site is...

Our records indicate that your product is covered under Apple's Limited Warranty which is estimated to expire on 26 October 2008.

Your product is not eligible for complimentary phone support.

If you believe that this information is inaccurate, learn how to update your coverage status. Please put your sales receipt in a safe place. You will need it for warranty validation.

Extend your service and support coverage for your product with the AppleCare Protection Plan. If you have already purchased an AppleCare Protection Plan, make sure you have registered it.

ZENER

Something stinks there. I'd call them with proof of purchase and reinstate your statutory 1 year warranty.

Sounds like PC world were massaging the figures to impress Apple over sales numbers and registered the machine them selves as if they'd bought it.

OT. Your iMac is one of those capable of taking and using 4GB, no question about it. I must be down to timing issues or some other difference in the RAM. Did you say the machine would boot with just a single 2GB module installed ?

ZEN

babypink

i would 100% chase this up............scan your receipt, call Apple with scanned receipt ready. Tell them it's FUBAR'd and offer to email the scanned copy of the receipt.

Your warranty begins from date of purchase, not from the date PC World decided to play silly buggers.

chrislad

Just an update for ye. Emailed Crucial after I exhausted all avenues here. I sent them copies of what my system profiler said about the memory, and a general overview, along with the model number of the iMac. I got the following reply.

Hello,

Thanks for your e-mail.

It looks like the memory was ordered against the incorrect system. Your memory is 667MHz so we will need to exchange the 800MHz memory you have got for the slower speed.


So there we go. It was 800Mhz RAM, even though System Profiler was showing it up as 667Mhz. The strangest thing is that I used the Crucial Memory program to scan my system and choose the memory I needed, and that picked the wrong one. Either way, Crucial are exchanging the memory with no issues, so I should have that next week.

Thanks for all your help.

babypink

cool!!

yeah i don't trust the program......better off using the drop down menus to tell the site exactly what machine you have.

glad they're sorting you out.

ZENER

I'll reserve my opinion on this until you actually get it working. Intel chipsets are meant to be very tolerant of RAM speeds and 800MHz RAM should be backwards compatible with 667MHz.

If what they're saying is true then you should get crashes as your memory usage goes into the expanded 2GB range. Or when you have a 2GB module in Bank 0 it should cause problems too. Did you actually get the system to start with only a 2GB 800MHz module installed by the way ?

ZEN

chrislad

Yup, it started with just the one stick in.

ZENER

chrislad wrote: »

Yup, it started with just the one stick in.

This kind of proves there's nothing wrong with the modules then. Doesn't it ?

ZEN

chrislad

*shrugs*

I'm just going by what they say. For what it's worth, I didn't notice any massive difference in speed between 1gig and 3 gig, for say, converting a 1.2gb .mov file to a iPhone friendly version. Was taking about an hour with 1gig, and the same with 3 gig.

J-blk

chrislad wrote: »

For what it's worth, I didn't notice any massive difference in speed between 1gig and 3 gig, for say, converting a 1.2gb .mov file to a iPhone friendly version. Was taking about an hour with 1gig, and the same with 3 gig.

Video encoding in particular is very CPU-heavy so I don't think you'd see a big difference with the extra memory. The memory should help though with the speed of some applications, the amount of stuff you have open at once and working with large files in things like Photoshop. When I got my MBP, it came with 2GB installed and having VMWare Fusion running XP with 1GB dedicated to it plus another 4-5 apps open in the Mac OS was causing slowdowns - once I upgraded to 4GB, those were all gone.

Still, I'm interested to see what happens with the replacements you get from Crucial - I've read through the thread and still don't get how the speed of the memory could be the problem...

chrislad

Got my new memory today, and I'm now running an iMac with 4gigs of memory. Guess it was a speed issue. I said I'd let ye know as it's probably still keeping some of you awake at night.

J-blk

chrislad wrote: »

Got my new memory today, and I'm now running an iMac with 4gigs of memory. Guess it was a speed issue.

Cool - good thing it ended up being the memory and not something on the Mac side, that would've been more of a hassle... Thanks for letting us know how Crucial handled things too - it's good to know for future reference, though thankfully so far I've never had any problems with memory from them.

chrislad

No worries. Thanks to everyone for all the help. Much appreciated. Kudos to Crucial for their quick response and solution too. Great company, and much recommended. It's the 3rd or 4th time I've used them and they've been great each time.

Simon201

Just curious Chrislad did you have to pay the 14 euros or so to Fed Ex in Dublin to receive the memory from Crucial?

Sad Professor

Glad to see you got this sorted, chrislad.

Simon201, I had memory replaced by Crucial a while back as well. It was delivered by UPS and I didn't have to pay anything, just the few euro to send the old chip back first.

Simon201

yeah I got some memory from them in Feb delivered the same way straight to my door with no duty payable - was only $24 though - this time it was $100, maybe there's a threshold that they have to charge duty above I dunno? And I thought that there was no duty payable on any internal computer parts?
Ah well still beats Apple.ie's €320 by a long shot!

Sad Professor

Oh you meant customs. In that case you've nothing to worry about provided you ordered from the EU or UK site. If you used the U.S. site I'm not too sure though, probably.

A note re: FedEx, they don't charge you for customs/duty at the door, they send you a invoice a few weeks later. And they declare everything so there's no getting lucky. UPS are the same.

whiterebel

Simon201 wrote: »

I'm rather curious about what you're saying there, like the only person to 'register' (if that's what you mean) the machine after purchasing is going to be the purchaser - i.e. you (and not Apple) - after it's been purchased. Surely the serial number should not be 'logged' at all until you did it yourself?
There certainly seems to be some strange goings on in PC world if your Apple TV thing has the same purchase/warranty discrepancies!

In olden days, some PC world demos were registered on the Apple system, and sold on months later. When Apple brought in the new Peoplesoft system 4/5 years back, the serial number used to self populate with the shipping date on most machines. Problem was, it could be weeks or even months before they were bought by an end-user, and more and more customers used to have to fax through proof of purchase. I brought it up many times, but was roundly ignored. it seemed to me to be a nice sneaky way to shorten the warranty period.

chrislad

Simon201 wrote: »

Just curious Chrislad did you have to pay the 14 euros or so to Fed Ex in Dublin to receive the memory from Crucial?

No, I ordered from the EU site and all produce from EU countries is customs free. All I had to pay was return registered post of about a fiver.