Late 2010 Core i7 iMac Shutdown

I am having the same issues. Read my thread on this.
http://discussions.apple.com/thread.jspa?messageID=12235181#12235181

I think the problem lies with the Imac ( can not cope with 16 Gig) and not the ram. I have tested the ram with 8 Gig (OWC) and no problems. Ran AHT and Rember ( a kind of mem test recommended by OWC)

peterwillem

Its small comfort that there are many other iMac users out there having exactly the same or very similar problems to my own. I've already had my iMac back for a screen replacement, and I had them check out the random shutdown problem.
They replaced the screen, and thought there was no problem with the random shutdowns after bench testing it for 48 hours.
I'm now having a repeat of the random shutdowns that I've had since the second day..
I've run it without anything connected to it, I've run an SMC and PRAM reset, I've run the Apple hardware test twice, and I've removed and reset the RAM modules.
My final test will be to remove the third party RAM ( RAM America ), and install the Apple RAM.
I've noticed at times that the top of the iMac gets very warm to touch.. even with little use or load. The ventilation slot could be bigger to allow faster cooling.
I've been using a Mac since 1983, and this is my 15th Mac. I know most of the ways to resolve Mac problems, but this one has me beat..
I only hope that Apple are aware of this issue through forums such as this. There has to be both an answer and a fix for this most annoying problem.
The question is - Is it a software problem, or is it a hardware problem "?

I just want to jump on here and write that I am also experiencing these random shut downs. Same set up... iMac mid 2010, 27", i7, 16gb ram. It's very depressing.

@dopepope, are you using OWC ram as well?

I am having the same problem and lately seems like I am able to reproduce the shut down but not all the time. I use Aperture 3.0.3, the computer have been shutting down by itself more than 8 times in the last nights while I am syncing photos with Facebook.

Hi Edmond,
Is it correct that you are using only 12 Gig ram? If so than it is possibly another problem.
If you are using 16 Gig ram, than what brand? (Apple, OWC, Crucial....etc)

peterwillem

I am not convinced that it's the memory problem. I haven't run Aperture tonight all night and was running Adobe Lightroom 3.2 and no shutdown so far.


Here is my memory info:


Memory Slots:

ECC: Disabled

BANK 0/DIMM0:

Size: 2 GB
Type: DDR3
Speed: 1333 MHz
Status: OK
Manufacturer: 0x80CE
Part Number: 0x4D34373142353637334648302D4348392020
Serial Number: 0x811C9E4F

BANK 1/DIMM0:

Size: 2 GB
Type: DDR3
Speed: 1333 MHz
Status: OK
Manufacturer: 0x80CE
Part Number: 0x4D34373142353637334648302D4348392020
Serial Number: 0x811C9E02

BANK 0/DIMM1:

Size: 4 GB
Type: DDR3
Speed: 1333 MHz
Status: OK
Manufacturer: 0x857F
Part Number: 0x483634353155363446393333334700000000
Serial Number: 0x00000000

BANK 1/DIMM1:

Size: 4 GB
Type: DDR3
Speed: 1333 MHz
Status: OK
Manufacturer: 0x857F
Part Number: 0x483634353155363446393333334700000000
Serial Number: 0x00000000

I quite agree with you.
With 12 gig ram these shutdown problems are not happening , according to all the threads in this forum.
And in your case it might as well be caused by using Appertur or doing something that uses a lot of ram.

peterwillem

Message was edited by: peterwillem

Hey guys, located this thread via google in efforts to find a solution for the 27 iMac i7 with 16gb of RAM. I see you have a few threads about this and wasnt sure which would be best to reply to. This thread had the most recent post.

So I too am having issues with my 16gb of NuRAM. I kind of suspected it was too good to be true (getting 16gb of ram for under $400). I also bought 8gb of NuRAM for my 2009 15 MacBook Pro. No problems so far.

So what solution have we discovered if any? I know that this isnt a heat issue since the past 3 shutdowns have been on light use and normal temperatures. Also I read I believe on MacRumors that people were having problems with the memory causing their iMac to Reboot. Mine simply shuts off. (Incredibly frustrating when spending hours in After Effects & Final Cut).

I also notice that most of my shut downs have been while using Safari (uploading a videos to Vimeo). Or other rather random things like converting songs in iTunes.

I am trying to decide whether to try the OWC memory or just suck it up and get the samsung memory from Other World Computing.

I would not try OWC ram, at least not 16 G. I my self and a lot of others have the same shutdown problems with 16 G OWC ram. So far no solution, only use less than 16 G ram.
There are some who bought Samsung factory ram, also from OWC, and that seems to work. Check all the threads about this issue.

peterwillem

Same here, new 27" iMac i7 and 16GB Ram from OWC. The hardware tests says everything is OK. I had a 27" iMac i5 before with 16GB Ram from OWC and no problems!

I'm also experiencing random packetloss (wired ethernet).

Apple needs to address this quickly.

I have now had my computer at Tekserve being looked at for over a week. Got the call this morning that no issues were found and all diagnostics came back clean. They offered to replace the power supply. I'm not sure that will solve the problem. This really *****.

Thanks for the info. I have been using only 12 gb of ram for the past week now and havent had a single shutdown. I guess I am going to return the OWC NuRam memory and just purchase the samsung memory instead. Id rather pay a little more if it is reliable.

I too have only recently experienced this problem and only after I went to 10.6.4 If Apple technicians are checking this thread and I'm sure they are, I bought mine in Sept and immediately installed the 16GB kit from NuRam via OWC. When on 10.6.3 I didn't have any problems at all and I didn't even boot up with the original Apple installed ram although I've kept it just in case.
My shutdowns are not too dissimilar to Apachestyle's if it happens there's no warning and no auto reboot as in a power failure which I have checked off that option under System Preferences.
However, the strange things I noticed and maybe this will be helpful to Apple:
1) When I restart my iMac it returns my desktop to a semi previous state. What do I mean by that?
A) I normally turn down the brightness before going to bed for the evening since I always listen to music before I go to sleep, but while using during the day I have the brightness turned up a bit. It returns the brightness level down like it was at night.
B) An updated program I downloaded days ago returns to my desktop and I have to keep ejecting every time it shuts down and I restart it. In case you're curious the update was for MagicJack.
2) Not that this means anything but another weird bug is my brand new Apple remote that's paired with my iMac isn't recognized to activate Front Row but may start working, in most cases when I use my iPhone's 3rd party app RowMote.
3) I did run the latest OnyX app and do a complete cleaning and I noticed the iMac appeared to be a bit snappier and after a restart my brightness level returned to the correct level for daytime inside lighting.
4) I also did the big 3, NVRAM, SMC resets and ran the Apple Hardware test and nothing was shown to be bad. I ran the full & complete test. (I was surprised it looked like an old OS9 application though! LOL)
Hopefully 10.6.5 or 10.6.6 may address this issue. I'm not convinced it's a hardware issue yet, including the 3rd party ram.

I have the same problem like the most of us here:
iMac core i7 2,93 after a week i bought it (that was a month ago) i upgraded to 16gb ram from OWC NuRam 4x4gb.
I did the SMC , the stand by and restart for 3-4 days i thought the problem solved. Today that happened 3 times (random shut off while i was doing just simple browsing and no something heavy , the computer temp was cool)!!! then i call tech sup. and i take the imac with me to the Apple store, they check everything and the diagnostic at the Apple store shows no problems. While i was there we did the PR reset (3times) and updated to the 10.6.5 . They offer me to leave the computer there to do 24hr heavy tasks test, but i prefer to leave the case open and i ll check that again by my self (just in case everything is ok now!). They told me that they first will try to change the power supply!!! if i leave it there and the problem re appears. So im going to try for few days and ill keep you posted.
Btw: i know its off topic my imac has an sd card instead of xdcard reader is anybody else here notice the same on his/her latest imac 27"???