iMAC Retina memory Upgrade issues

Kilobyte Kid

Re: I too am a member of the club

I noticed that Amazon has suspended sales of the 16GB Crucial memory kit recommended for the Retina iMac and that the 16GB kit recommended through the system scanner is out of stock (Your scanner ID:C2D6432231D926C3).  Could this be because Crucial is not shipping memory until this issue is resolved?

Kilobyte Kid

Re: iMAC Retina memory Upgrade issues

Thanks so much for posting this - I've had exactly the same experience. New Retina iMac with 8GB of Apple RAM worked fine - but started crashing after installing Crucial 16GB kit. The system failed memtest with the Crucial RAM installed, but passed as soon as the Crucial RAM was removed. I sent back the Crucial RAM once, received new RAM - and again it fails memtest.

Three of the top discussions in the Crucial Mac forums are about this issue (16GB Crucial kits not mixing with Apple RAM) which suggests that there's a problem. I think I'm going to ask for a refund on the Crucial kit, and wait to see if Crucial's engineers can fix the problem, and release an updated product.
Bit Baby

Re: iMAC Retina memory Upgrade issues

I have just installed a 16GB Crucial RAM upgrade to my late 2014 iMac Retina 5K, making a total of 24GB RAM. I experienced no problems mixing the Crucial RAM with the 8GB Apple RAM installed from new.

Kilobyte Kid

Re: iMAC Retina memory Upgrade issues

[ Edited ]

Hi, I have been searching for days for posts on forums that relate to my issue. I have an iMac 27" 5k retina late 2014 model (brand new to me) factory refurbished. No problems within the first 14 days in which I could have returned it. On the 13th day I added 16gb of new ram to the 16gb of Apple ram I already had (sorry, I added OWC Ram but please keep reading). Still worked fine until the 15th day. Turn on iMac it started fine then when I came back to it, it had totally black screen & absolutely no signs of life. At that point Apple ram was in slots 1 & 3 counting up from bottom. Owc in slots 2 & 4.

 

Took iMac to the local authorized Mac repair.  They agreed it was dead. BUT, then with no repairs it started working on their workbench. They tested for two days. Nothing wrong. I went to pick it up. He tried to turn it on. Dead again. We stood talking in the shop with the dead iMac plugged in, after 10 minutes it booted with no one touching it. Shop techs suggest sending it to Apple. According to Apple Care, if the machine does not fail while hooked up to their testing equipment, it doesn't matter if won't start. My local Apple Authorised Repair shop can't deal with  the problem. OK, but it's the weekend. So I take it home and start testing the ram. I run with only Apple ram, then only OWC. I'm focusing on slots 2 & 4 because those were empty the first 13 days when it was having no problems. I get Bad Ram 3 Beeps with OWC ram. I think it's the culprit. But then I check each stick individually in each slot. Now I get the Bad Ram 3 beeps with APPLE ram in slot 2. repeatedly. OK,  think it's a slot problem.

 

But on the 8th test of that Apple stick in the suspect slot, the slot has no problem with Apple or OWC. What the ****? BTW, each time I test a ram stick, I run Apple Diagnostics. But Apple Diag is pointless. The iMac either refuses to start with Black Screen (no cursor, no boot) or it does the Bad Ram 3 beeps, wait, repeat, or it starts right away and runs until I turn it off. You can only run Apple Diagnostics on a live machine.

 

Currently it is running with the one stick of Apple ram that failed most often. I have no other ram in it. This is the slot that has produced the Bad Ram beeps. I am running Memtest repeatedly hoping to get some reaction. After I read your discussion I thought maybe the black screen was caused by mixing the ram, BUT that doesn't explain the individual Apple ram stick getting the Bad Ram 3 Beeps from slot 2 and yet it tests fine with Apple Diagnostics.And so do all the others. I am tempted to take out the Apple & the OWC, and try Crucial at this point. But maybe the slot is intermittently bad. 

 

If I send my iMac to Apple, I bet it will come back from them with the same problem. Did you guys get any further in resolving the ram mixing issue? Anybody have any suggestions? BTW, yes, ALL STANDARD TESTING PROCEDURES have been followed by me, by the local Apple repair. So this is way past trying new cables, outlets, NVRAM, SMC, whatever.

 

Thanks for reading.

Kilobyte Kid

Re: iMAC Retina memory Upgrade issues

Same issue but on iMac 27" (late 2013). Asked for RMA but reading of your expreriences I guess I'll change my mind and ask for money back, instead of ram replacement.