27" Core i7 iMac blacks out then restarts itself for no reason...

Hello,

I've been having a problem with my iMac (i7) as well. Only had it a few weeks and it locked up on me three times already. I add memory too:

Kingston 4GB (2 x 2GB) DDR3 1066 (PC3 8500) Dual Channel Kit Memory For Apple Model KTA-MB1066K2/4G (Newegg Item #: N82E16820134827)

My lock-ups never restarted the computer. The first lockup I believe happened when I tried to wake it from sleep mode, so the screen was black. I couldn't get it going until I held the power button down and physically restarted it. The second time it froze I was in iTunes. It froze with iTunes on the screen and the mouse and keyboard were un-responsive. I even tried throwing an SD card in (looking for it to mount) to make sure it was locked up and not a blue tooth problem with the wireless keyboard and mouse. The third time it froze was a few days ago when my son was playing club penguin. Safari was the only application running.

Yesterday I ran a Memtest (2 passes) and it said everything was fine. Since then I pulled out the 4GB (Kingston) of memory. I'll wait to see if it freezes again. I even spoke with Kingston and they said the memory I ordered was the exact one for that machine. I wonder if anyone that actually bought the 8GB's from Apple is experiencing any of these problems. Does it have something to do with Snow Leopard handling 8GB of RAM or is it because of the third party RAM. I don't know what else to try.

Had another uncomannded restart last night. Took the extra crucial memory out this morning and will see if this happens again.

My computer is also blacking-out over and over. It's like its going to sleep and then I wake it up, but it won't stay awake! After I restart the stupid thing it'll stop cycling of and on. I've done all the unplugging and PRAM reset thing and nothing helps. I'm taking it in to see a "Genius Bar" expert in a couple of days. Will see what they say.

I have done no upgrading and have nothing attached other than the ethernet cable.

I've done no upgrading. All of the 8GB of RAM are factory installed by Apple.

I yanked the crucial ram and all my worries disappeared.

I'm starting day 2 without the extra memory. Went all day yesterday without a restart. I also did one other thing that might be worth mentioning. I went into the Energy Saver panel and toggled scheduled restart on and then back to off. Probably not a factor though.

Message was edited by: Ravenwood61

hi,
i've read this post and would just like to add something, incase it should help anyone...
a few weeks ago i removed my original sdram & then put them straight back in (i had been sent the wrong stuff which i was going to upgrade with) and since then my mac has had constant black-outs, so i don't think it has to do with third party hardware. at least not in my case.
my new sdram has now arrived (crucial) & i've put them in, so i'll wait & see if the black-outs continue.
jonathan

Day 3 has gone by and there were no un-commanded restarts. I also left the iMac sleeping last night instead of shutting down as I usually do, and still no restarts. I'm a little leery of installing this firmware patch that just got released because everything is running so well right now.

I'm on day 8 with no problems at all (after pulling out the extra kingston ram). There must be a slight issue with the ram.

Day 4 down and well into day 5 with no restarts. So it appears to have been the memory. What does this mean? Is it a problem with a 4x2GB configuration? A problem with 8GB total? Or is it a Crucial memory problem?

The most likely cause is a fault in the RAM module. Apple sells the 4x2GB config, and it is a popular customization, so I don't think there is anything inherently wrong with having four 2GB modules installed.

It is may not be a general problem with Crucial's RAM either, just a problem with the modules you happen to receive.

I have the same problem on a 27" I5. I installed the firmware update on the day it came out and now have the problem when I don't think I had it before

oldmacgeek wrote:
I have the same problem on a 27" I5. I installed the firmware update on the day it came out and now have the problem when I don't think I had it before

When you refer to "the same problem", are you referring to the black-out restart or the flickering problem that the firmware upgrade was supposed to address? I have not upgraded firmware and have not had any un-commanded restarts since I removed the Crucial memory on 12/19/09.

Message was edited by: Ravenwood61