Chosen Solution

Hello I have Late 27" 2015 A1419 iMac. EDIT: I installed a new Apple/Samsung SSPOLARIS MZ-KKW5120 PCIe NVME SSD and sometimes my iMac won’t recognize/detect it. However, whenever it does recognize it, it works fine until my computer goes to sleep (or deep sleep?).  When I wake the computer up from sleeping, it restarts because of a problem, a panic report corresponding to kernal_task.  It then stops detecting the SSD.  Does anyone know why this is happening? EDIT: Is the SSD incompatible or is it a faulty SSD? Or did I need to have High Sierra on my system before installing it? EDIT: This article mentions that my iMac can upgrade to the Gen 5 SSD’s: https://beetstech.com/blog/apple-proprie… I’m thinking it might be a compatibility issue.  I noticed the MZ-KKW5120 was wider/“Fatter” in appearance than the original PCIe NVME SSD in my system. The MZ-JPV512R looks like it is closer to the size of my original PCIe SSD. Maybe I just bought the wrong SSD and need to get the MZ-JPV512R? I get this from the Problem report: Panic Report *** panic(cpu 0 caller 0xffffff7f9367eb92): nvme: “InitializeNVMe error = 0xE00002D7\n” EDIT 2: I actually found out the answer from two different sources. Some guy from eBay: “Yes this is a known issue. If you dig through the internet, you’ll find users that have experienced this exact issue. It has to do with the iMac chipset for that model year which affects a small percentage of those iMac owners. We’ve seen this same issue as well with UK/Aus iMac models as well. The AHCI model is not as fast as the NVMe since it doesn’t use that communications protocol. (~2200MB/s Read 1700MB/s Write on x4 link width iMacs). Since the newer versions are more efficient, there is no throttling under heavy loads. Also note that the deep sleep issue is just a small portion of the problem. Users have also complained about corruption and data loss. " This one was from Beetstech: “I don’t think your SSD is faulty. Looking back on our testing of SSPOLARIS controlled NVMe Apple drives it appears we noted a kernel panic on wake from sleep on some 2015 A1419’s.”

I actually found out the answer from two different sources. Some guy from eBay: “Yes this is a known issue. If you dig through the internet, you’ll find users that have experienced this exact issue. It has to do with the iMac chipset for that model year which affects a small percentage of those iMac owners. We’ve seen this same issue as well with UK/Aus iMac models as well. The AHCI model is not as fast as the NVMe since it doesn’t use that communications protocol. (~2200MB/s Read 1700MB/s Write on x4 link width iMacs). Since the newer versions are more efficient, there is no throttling under heavy loads. Also note that the deep sleep issue is just a small portion of the problem. Users have also complained about corruption and data loss. " This one was from Beetstech: “I don’t think your SSD is faulty. Looking back on our testing of SSPOLARIS controlled NVMe Apple drives it appears we noted a kernel panic on wake from sleep on some 2015 A1419’s.”

Hello John and Dan I’ve unwittingly stumbled into this issue too, after upgrading the drives in my Late 2015 iMac. I put in a WD Black drive and it is recognised and works fine, until waking up from sleep when the kernel panic occurs. Can you recommend a 500GB blade that would work with the slower motherboard? Or if I put the WD drive in an external enclosure would that get round the issue, or would the motherboard have the same throttling issue too? A real pain to have to strip the screen off again….