27" iMac i7 spontaneoulsy shutting down

Kilobyte Kid

27" iMac i7 spontaneoulsy shutting down

I have a nearly new 27" iMac 2.93GHZ QUAD-CORE INTELCORE I7 that I have upgraded to 12GB RAM with:

 

CT1412114 (Part Number: CT2KIT51264BC1339)

 

And 4 times now the computer has randomly shut down.  I keep the computer on 24x7 and I'll go to my desk to use it and it's powered off.  Turns off in the  middle of the night sometimes, sometimes during the day.  It's totally random.  There's an Apple thread on the issue:

 

http://discussions.apple.com/thread.jspa?threadID=2473276&tstart=0&messageID=12716627#12716627

 

No response from Applie but many of the commenters who are experiencing the problem seem to have performed a third party RAM upgrade.  Has anyone else experienced this issue with Crucial RAM?  Is this a known issue you guys are tracking?

 

Thanks,

Pete

57 Replies
Mo Betta Heat Spreada

Re: 27" iMac i7 spontaneoulsy shutting down

Hello,

 

I have not heard of the issue you are describing here.  I'd recommend contacting our Technical Support department to troubleshoot and discuss this issue.  I looked over our sales history of the parts with this system and it looks great.

 

Be sure to use the proper link for your location, and reference this thread so they can see the troubleshooting you have done.

US Customer Service

UK/EU Customer Service

Dude, Crucial Employee, US
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Kilobyte Kid

Re: 27" iMac i7 spontaneoulsy shutting down

Don't have a the new iMac but I have that exact problem with the 8gb upgrade for the mid-2009 MacBook Pro 15".   Waiting for the RMA number which seems to be taking forever.

Kilobyte Kid

Re: 27" iMac i7 spontaneoulsy shutting down

HI,

 

I have a new 27" Imac with a 2.93 I7.  I bought 16 gigs of ram from crucial and have not experienced any shutdowns whatsoever.  I built my first PC in 1993 and have had two other macs.  This is what i have learned along the way.  Intel Processors are very sensitive to dissimilar ram, they really do work best with matched pairs of ram.  In fact for a number of years it was a requirement, while this may have changed (not sure to tell you the truth) when i buy ram today i make sure it is from the same manufacturer, same exact ram to the greatest extent possible, that is the major reason i chose crucial.  I loaded up the ram (used some very cool Utube videos made by some really neat folks) to be sure i knew how to open and remove the old ram and made sure the ram was seated in each position very securely.  Started the Imac up and it works perfect, faster than all get out.

 

As I understand it, dissimilar ram can cause something called internal kernal crashes.  Where some of the ram is in fact competing with other types of installed ram, hence the need to install all one type of ram so if you choose to use two four slots as i chose to use, i made sure i replaced the apple installed ram with all one type.  Reason is i don't really know whose ram it is in the Imac.  I can assure that the Ram i purchased from crucial is all the same.  

 

Remember manufacturing processed really do matter and they really do count.  Consider for a minute the difference in price between an ATI video card made by different manufacturers.  In my PC i have one made by Diamond, I would also choose VisionTek but the others have gotten some bad play on Amazon.  Don't believe me, check it out.

 

My advice and you know what they say about advice (cheap as **bleep**) is to spend the bucks and replace or use only one type of ram, from one source, one manufacturer and yes only one type of size of ram, meaning this.  If you choose to want 8 gigs of ram use 4 slots 2 gigs each or two slots 4 gigs each.  I would not mix sizes of ram so if you use 2 gigs in one slot do not install 4 gigs in another, from where i sit, it is not a good idea.  As a Navy Seal friend of mine once said, Go Big or Stay at HOME!!  That is, buy the right stuff or leave it alone!

Kilobyte Kid

Re: 27" iMac i7 spontaneoulsy shutting down

I too am having random shutdown issues my new 27" i7 iMac.  I am trying to add 16GB of Crucial memory to the system (confirmed that it is the correct modules).   It worked just fine when I lower it back to 12GB (4GB of Apple RAM and 8GB of Crucial).  

 

I have tried all the tricks listed here (PRAM reset, SMC reboots, etc.), the only thing that seems to work is the “32-bit plan”.  I have tested this theory several times (running the same program in 32 and 64 bit mode) and it appears to work properly without any shutdown in 32-bit mode (Safari, Aperture, Mail and Ripit).  Maybe there is a connection between 64 bit programs trying to access 16GB memory?  This problem is obviously an isolated issue and not a systemic one across all iMacs.  Again, I am researching, testing and talking to both Apple and Crucial about this issue. 

 

I will tell you that the folks at Crucial are outstanding!  I really want to use their product, but I need an iMac that can run at full capability (lots of video editing and other high demanding task).  I will try to figure the problem out over the next few days, but if it doesn't work out, then I will have to send the memory back and try another solution.   

 

Good luck, I would really be interested in finding out what the problem is.

Kilobyte Kid

Re: 27" iMac i7 spontaneoulsy shutting down

I put 16GB RAM into a new iMac 27/ Quad i7 and after three days had a sudden shutdown.  The log simply said 'Improper Shutdown' - on reading the forums I wondered if it was the RAM, However, since then it has been working fine for 24 hours.  I will be interested to see what the solution will be for this issue and fingers crossed my system shut down was completely unrelated.  Crucial emailed a offered a full refund so I am very impressed with the service.

Kilobyte Kid

Re: 27" iMac i7 spontaneoulsy shutting down

Can I ask within what time period did the shut down's happen? I have had it once after the first three days, but non in the past two...... Just got the mac on Monday....

Kilobyte Kid

Re: 27" iMac i7 spontaneoulsy shutting down

Same iMac, same 16 Gb of Crucial RAM, same random shut downs. No rhyme or reason. Sometimes while I'm working in multiple applications, sometimes when the machine is asleep with no applications open at all. 

 

Anyone have any  suggestions. I'm a big fan of Crucial, but this is a very serious disruption to my work, has blitzed a backup drive and corrupted a couple of major project files. 

Kilobyte Kid

Re: 27" iMac i7 spontaneoulsy shutting down

Have you had any luck avoiding shutdowns. I did the same thing you did to the same machine. I agree the folks at Crucial are great, but the problem is not resolved for me. Just when it goes two or three days without a shutdown and I think the problem is solved, it will shutdown 4 or 5 times in a single day. Seldom when it is under a heavy load. 

 

So has anyone solved this issue?

Kilobyte Kid

Re: 27" iMac i7 spontaneoulsy shutting down

For some reason I have never had any more shutdowns and that's into a month now!  I have ahd two kernel panics when trying to partition my internal drive but that I can live with