Several sudden shutdowns on new iMac

I had the same random shutdown problem as many others here, and solved it by replacing my 16 GB of OWC RAM in my mid-2010 27" iMac with 16 GB of Samsung RAM (also from OWC):

http://discussions.apple.com/messageview.jspa?messageID=12940872

Excuse me for butting in, but following this thread out of interest I have to ask perhaps a silly question ? Are all affected computers 27" models? I don't remember seeing any references to 21.5" models.

Hi,

I'm having similar problem today. 5 shutdowns of iMac 27" (2010). 16 GB of Memory (not Apple).

Ram has passed all tests made with Rember or Tech Tool Pro.

Can this problem be related to Flash player or Firefox?

All 5 shutdowns that I've experienced ocurred when I was visiting the website MARCA (www.marca.com) with Firefox. I'll try other configurations tomorrow, but it shutdowns randomly. For now, no problem working or visiting other sites with Firefox, no problem viewing the same site with Safari. But the iMac still shutdown randomly when I visit this site with Firefox.

Any idea?

Does this problem occur only to iMac's that have had RAM added to them?

I think occurs when RAM is not Samsung. Apple sell their iMacs with different RAM modules. When it comes with Samsung, seems no problem. When it comes with other, some people are experiencing shutdowns.

When comes with Samsung, but we change the RAM modules with others (Kingston, CSX, OWC), the problem appears again. But may be it's possible combine some modules from Samsung with other different to obtain more stability, perhaps no 100%.

Thanks peterwillem.

I've uninstalled 16 GB RAM (CSX) and installed again 4G (Samsung, included with iMac). No problem now. Perhaps I will try to change CSX to Samsung to use 16 GB.

It's curious that I can force the shutdown problem visiting the website Marca.com with Firefox and all plugins actived (Flash, Shockwave, Java, etc.) But sure the problem is RAM, not this site.

UPDATE:

A user by the name of Gianfri has confirmed that OWC recently "tweaked" their RAM to address the issue.

reference: http://discussions.apple.com/thread.jspa?threadID=2548180 (see near bottom of page 13 in that thread for the comment from user Gianfri).

For those still having the problem (with OWC RAM), I'd suggest contacting them to get the RAM replaced (OWC gives lifetime warranty on their RAM, so they'll replace it).

Peter,

Would it be helpful if you had an old friend or a new one wink*wink to help you as a middle man in the shipping & handling? Here in the states at least we can ship goods as gifts to the recipient. There will probably still be a tariff charge or whatever but would that help you in your situation?

Let me know if I can help in any way since I've noticed you're doing all that you can to assist everyone here in the forums on this matter. 🙂

PS
Even though I didn't get the OWC ram I opted for the NuRam, only because it was quite a lot cheaper at the time I purchased it, I hope that both manufacturers will cooperate in replacing the incompatible ram modules they sold us even if it was Apple's fault perhaps.
I'll be contacting both OWC and Newer Technology and find out if they're offering a replacement program. As soon as I receive an official reply and hopefully some help I'll pots the info here.

And another one bites the dust...
Already posted feedback to Apple.
Bought it beginning december and have been struggling since to get a new one.
Have spend at least a 1000€ to finally get a new one.
And now I read all these threads of people suffering the same issue.
I hope the new one works.
But if I'm not lucky it has Samsung modules installed, it seems we might get the same problem again.
I'm also amazed we all just accept it and go with less memory ...than what we paid for!?
Apart from having to wait 2 months for a solution. I have to make a living in order to buy new computers...
That's not worthy of Apple and by any means a joke in consumer rights...
Imagine buying a Porsche that shuts down when going faster than 50!?
Who would buy that?
I hope Apple takes responsability and does something about this soon!
It has been one of my favourite brands.
But being sneaky about such an issue isn't very ethical.

Could someone please explain how I check manufacturer of my RAM? The manufacturer code in my system profile is 0x80AD. Who is this?

I have 8Gb RAM as purchased from Apple, no added memory, and I am getting same problems of shutdown. It is truly crap.

The shop (Macnificos, Spain) where I bought 4 modules of 4 GB of Ram that causes random shutdowns on my iMac 27, has been in contact with the distributor and manufacturer of CSX Ram because some other clients experienced the same problem.

They affirm that shutdown problem is an electric problem of iMac, not a problem of Ram modules, and they are sure that can ocurr when the machine has 16 GB of Ram installed and with some specific modules. CSX can't found any problem on their modules, so they think their RAM is OK, and assure that the problem is random and also can ocurr with Samsung RAM. They think perhaps my modules are defective. I'm not agree with this explanation.

They accept to change my four 4GB modules of CSX RAM with four new identical modules. I will try it all next week, and I will warn you if the problems persist with the new modules, but I'm sure that shutdowns will be continued ocurring because the modules that they're sending to me are identical to that already I have.