Q: 27-inch / 27" iMac Random Shut down

I just received the replacement Mushkin Hynix memory this morning and unfortunately it failed. I installed both memory kits and the computer failed to boot with POST chime.

Then I installed one memory kit into BANK 0/DIMM0  and BANK 0/DIMM1 and left the other two banks empty. With one set I was able to boot and get the POST chime then get as far as the login.

I then got the kernel panic error with the transparent screen to reboot. Next I swapped with the other memory kit (2x4 GB) and the computer wouldn't boot, no POST chime. I also reinstalled the memory to ensure it seated correctly, the normal tech stuff.

After all this I replaced the memory with the original Apple Samsung memory and everything is working fine. I then contact Mushkin who agreed that its possible to have a bad chip on the memory. They're shipping the replacement via advance RMA (last RMA at my expense) but said they will test before shipping.

Mushkin have been great with this whole crappy experience but I'm almost to the point of thinking Apple has some sort of agreement with Samsung and forcing us to purchase from them (Apple) or Samsung.

I'll post again once the new memory gets here, hopefully there's better news. LOL

So there's some small hope after all. Guess I will have to call Mushkin on monday myself, and get another replacement. Any chance you can give me the name of the person you talked to, just incase i run into a unfriendly person...

The person that I spoke with was Tyler ext 104.  He setup the RMA and said that he would test the memory before sending it out. I said don't rush and take all the time in the world. I rather wait a bit longer and know that I'm getting memory that's good. Good luck with your RMA, I'll post again once I have the new memory installed and hopefully working.

Well i finally got a hold of mushkin, and we think we might have found my problem. Tyler mentioned that i should try each set (2 sticks) by themselves and see if one set was bad. In the process of removing the ram, I noticed that 1 stick did not say hynix on it. So they are going to send out a new stick. I thought there was something funny when i put it in, the ram stick edge color, 3 of them were green, 1 was brown. The brown one was not hynix. (that probably means absolutely nothing, but thought i would mention it just in case)

I went and checked mine, all are showing Hynix, had to use a magnifying glass LOL.  Good point though as I'm sure it could very well cause issues. My replacement memory should be here in the next few days and I'll post with the results.  Cheers

And yah, the color of the edge means nothing, I just recieved my 2nd replacement today. The 2 new (hynix chips) edges are also brown.

On the positive side, I ran my computer 24/7 since the 26th on 12GB with no issues. I'm now currently 16gb again, with all 4 ram sticks having hynix chips. Will post again if I have shutdowns.

OK how did you get yours so quickly? I'm still waiting for my 2nd replacement since the 20th of May. Maybe it has something to do with living in Canada, customs holds on to it for a couple of weeks just because they can!

I have a similar problem. I own a i5 27'' with 4 Go from the get go. I haven't used it much apart from browsing and listening to music or watching movies (about once a week since I got it in november 2010), nothing more.

I have been experiencing those weird shut downs for a few month now. After bringing my computer back to the Apple store, they kept it a few days and changed the power supply and called me up so that I come pick my Imac. A few days later, the same problems reoccured a few times.

The usual scenario goes like this: I put my Imac to sleep before I go to bed around midnight, and the next morning when I want to check my emails, there's no response from the computer when I press on the magic mouse or the keyboard.

At least, I see that I am not alone in that situation and that they(Apple) might be able to corner the real problem eventually (hopefully) so that I can stop worrying about this being a bad purchase!

I think I'm just gonna have to bring it back again to the geniuses since I'm no genius myself!

Good luck all!

Akitaguy, I would give them a call and see if you can't get a tracking number, just so you can see if they even shipped it out and shipped it to the right address.

MarcoV81, if you are only running 4gb of ram, I'm going to assume that you did not replace the standard ram. It sounds like you might have a seperate issue. The random shutdowns that people are experiencing in this topic happen when they max that ram out at 16gb. Anything less then 16gb normally solves the problem so far.

Just for curiosity, did you replace the ram at some point? I would pull out a stick of ram, and check the type/brand. (If its original, it should be samsung i believe). Have you also ran any ram tests (memtest+)?

Shadowhywind, I did not replace the ram, I have not run any ram test.

Just got the replacement memory delivered by FedEx very exciting was on the phone and the doorbell rings, had to restrain three dogs, Delivery person a bit nervous LOL   Will post once I've installed and hopefully it working.

Got the new replacement memory installed and CROSS my fingers and toes so far so good. If it fails this time then I'm sending the memory straight back to the reseller NCIX and bite the bullet and go with Samsung.  I must say though that Mushkin have been straight up when it comes to customer services, I can't fault them on this issue. The whole memory thing is always difficult to troubleshoot. The computer runs perfect but once I installed the 3rd party memory it started with the issues.

So I'll see how this memory pans out in the next few days, I'll run Aperture, Parallels and a game or two and see if it caves and goes south.

MarcoV81  I agree with Shadowhywind sounds like you may have a different issue at hand, have you pulled out the memory and reseated? Also reset the SMC  > http://support.apple.com/kb/HT3964 <

Resetting the SMC for Mac Pro, Intel-based iMac, Intel-based Mac mini, or Intel-based Xserve

If this doesn't resolve your issue Marco V81 then it's a trip back to the Apple store.

Good news so far the new replacement memory from Mushkin with the Hynix chips is holding on:

15:24  up 21:39, 2 users, load averages: 1.02 0.71 0.35

iMac-i7:~

I've run Parallels, Aperture 3 and a couple of games, that was last night after installing the memory, no shutdowns

  Model Name:          iMac

  Model Identifier:          iMac11,3

  Processor Name:          Intel Core i7

  Processor Speed:          2.93 GHz

  Number Of Processors:          1

  Total Number Of Cores:          4

  L2 Cache (per core):          256 KB

  L3 Cache:          8 MB

  Memory:          16 GB

I purchased RAM from macsales.com, the brand being OWC. I got 16GB, and so far it went almost an entire day without shutting down. I don't wanna jump the gun yet, I'll give it a week and report back here one way or the other, but so far, smooth sailing. I ran all CS5 Suite programs, Parallels, you name it, I through everything I could in there, and so far all's well. So looks like in addition to the Mushkin Hynix RAM, OWC is also good to go. Fingers crossed.

I've had the Mushkin memory for 11 days now and absolutely no issues Mushkin Hynix seems totally fine.

I've being doing a whole pile of crap in Win 7 (Parallels 6) also installed Ubuntu version 11.04 with the latest update from Parallels. Everything is working perfect! Also did a bunch of photo editing in Aperture 3 and watched

an HD movie on Netflixs.  Didn't close any programs, just ran everything to see if I could crash and burn..... but nothing. I'm now a very happy camper! Thanks to Mushkin for great customer service and support!