New 27" 2010 iMac i7 Memory Issues

My mid 2010 iMac I7 has operated over 6 weeks with 16 GB of ram without any memory issues. Two 4 GB modules were original OEM from Apple and two OEM 4 GB modules were purchased from MacRamDirect.com.

Other than a few reboots to update software my system has been running 24/7 the entire time.

Maybe it is a good idea to summarize your problem and the steps you have taken.
Use the following link for it, if you have not done so already.
http://www.apple.com/feedback/

peterwillem

Just a thought here about the Ram issues from someone who has a brand new 27 2.93 and who built his first PC 17 years ago when dip switches were the real thing to master on a motherboard and man was it a mother!! I also recently built a new PC where that is no longer the case wow what a difference but I am have been a Mac Devotee for the past 6.5 years. Believe me Virginia, there is a difference in how they work and do business. I like the Mac style more than the PC.

In terms of the RAM one thing I have learned and seems to be true on my new 27 is that intel chips are very susceptible to RAM from different manufactures as well as requiring to be in matched pairs. I just upgraded my Mac to 16 gigs of Ram I bought from the crucial.com website. Crucial seems to be a good manufacturer with a great return policy so it seemed to be a good idea to use their ram. So far (and yes it has only been a few days) the Imac is working perfectly. It is visually faster than with the standard 4 gigs of ram that comes with the 27. I made sure that when I replaced the Ram I bought four sticks together, meaning they would come in matched pairs for the system. I think this is an important thing to keep in mind because differing Ram can cause what is referred to as Kernel Crashes, where I believe this is right, the ram sort of competes with other dissimilar ram. Not a good thing!! So in terms of Labeck's original comment I would agree that the ram he pulled out is in fact not bad just in competition with the new ram from a different manufacturer and while it is the same ram is not the same ram really. Manufacturing process really count. When I built my PC I chose an ATI 5850 video card but I bought one manufactured by Diamond, I would have also bought a VisionTek but what I read on other boards says the other guys cards have a tendency to fail. Just something to think about and I hope this helps. Thanks for the good words from others posting.

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

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).

Same problem here - Started randomly turning off when I went from 8GB of GSkill to 16GB. Regularity was about once a week, then today I had it happen 3 times... I've removed two of the modules for now and will see if it comes back. This is totally lame.

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.

Received today 4 new modules of 4 GB CSX RAM. Same problem, after installing, random shutdowns.

So, no defective RAM, sure incompatibility Issues.

With 12 GB, 8 GB (2 modules) or 4 GB (1 module) no problem. With 16 GB, impossible to work.

Waiting a response from the shop for the possibility to change this RAM and get Samsung which does not produce shutdowns according to report several users.

As I've explained some weeks ago, I experienced random shutdowns with my new 2010 iMac 27" 2,8 GHZ when I upgraded it to 16 GB of Ram with 4 modules CSX sold by Macnificos.com (Spain).

This shutdowns happened many times when I was surfing the Web. Most of them happened when I visited Marca.com with Firefox, but surely the system could have shutdown while I was carrying out any other task.

There was no shutdowns when I downgraded the iMac to a 4 GB, 8 GB or 12 GB configurations with the same modules. The iMac shutdowns happened only when it was 16 GB.

After installing 4 new CSX modules the last week, my machine continued shutdown randomly.

Finally, I've received 4 new 4GB Samsung modules to replace the CSX RAM this friday, and I haven't experienced more shutdowns since I installed them.



My conlusions are:

1) Only Samsung modules can be used safely to configure the new 2010 iMac 27" with 16 GB of Ram, although modules from other manufacturers can work in certain specific equipment or for some users, but not all.

2) Similar problems on other models of iMac (iMac 24", iMacs from 2009) can don't be related to a Ram problem. The shutdowns happened on this other machines with the same symptoms can be produced by another problem.

3) In many cases, it's possible to use RAM from manufacturers as Kinston, Hynix, CSX, Corsair or OWC in the iMac 27" 2010 but only with configurations with a maximum of 4 GB, 8 GB or 12 GB. With 16 GB configurations, the modules of all this manufacturers can produce or not random shutdowns, althought the modules are provided by Apple when we bought the machine. Apple includes different manufacturer RAM to their iMacs, but probably only those suministrated with Samsung modules can work with 16 GB without shutdowns.

4) Of course, PRAM reset, SMC reset, completly Mac Os reinstall and other similar procedures doesn't solve the problem.

5) Apple don't know how to solve or fix this. Apple support offers changes of power supply, motherboard or complete machine, but no one of these steps solves the problem.

6) Apple isn't informing about this RAM problem, and their users and clients are completely disinformed. Everytime the problem appears on a new machine, its user has to spend a lot of time, perhaps sending its equipment to repair without satisfactory results, until he found the solution explained on this forum.

7) One more time, Apple is not behaving as we would wish. They would have to mention the problem to new buyers or at least to its technical support services so that they do not replace equipment, power supplies and other components without purposes. They would have to propose directly a change of ram memory to Samsung modules while their engineers investigate the problem and find a definitive solution.

8) If you are experiencing this problem, the only solution today is use Samsung RAM or configure the machine with less than 16 GB.



In order to finish, I want to be thankful to Macnificos.com by its amiability and help to fix my problem. They acceded to change my 4 modules of CSX for 4 modules of Samsung and now I can work without problems.