Big (Possibly GPU) Problems on 21.5 4K iMac 2019

[KingCornWallis]

Recently bought a 2019 21.5” 4K iMac with middle of the line specs:

CPU: i5 8500
RAM: 2x4GB 2666MHz RAM
Storage: 1TB Fusion (1TB HDD + 32GB PCIe SSD),
GPU: RX 560 4GB.

It was New Open Box from eBay, and from what I can tell has never been used.

I then performed an upgrade with the following parts:

CPU: i7 8700 (Used)
RAM: 2x16GB 2666MHz (Used; Micron)
Storage: 1TB NVMe SSD (New; ADATA SX8200 Pro) + M.2 Adapter (New; Sintech); 500GB SATA SSD (New; Crucial MX500)
GPU: No Change (duh)

High quality thermal paste (Thermal Grizzly Kryonaut) was used on the GPU and CPU. The MX500 SSD was not used for anything and is not relevant.

The macOS was updated to 10.15.3, Trim has been enabled, and Migration Assistant used for our data on a Mid 2010 iMac running 10.13.6.

So, now the problem. After the restore and initial usage, the machine was fast, but not as snappy as it should be for the hardware installed. I attributed this to all the indexing going on and the backup taking place. But after an nVRAM and SMC Reset, the computer really picked up speed and didn’t fall back.

Then the problems began appearing, that all seemed to point to the GPU failing:

1. iStat Monitors showed that while the GPU processor usage was extremely low but VRAM usage was often completely maxed out (All 4GB). This is without doing any visual tasks. Upon investigation it appears the Curating Process in Photos and maybe the Time Machine backing up could be causing this. Now it seems mostly stable (under 50%) but occasionally it will ramp back up. This is likely a non-issue based on my research
2. Artifacts began appearing on the screen, mostly elongated triangles. These could easily be removed by just dragging a window over the affected area, kind of like erasing them on a drawing board. See attached.
3. Next came the shutdowns…at some point when asleep it seems to shutdown. One time when I clicked Report after the problem was shown I read Panic CPU Caller 2 before the window was closed for some reason. Upon looking at the Shutdown log, all reasons for shutting down (a total of 9 in the last 24 hours) have been code 3 IE a Hard Shutdown. I know for a fact that I have only done this ONCE. Looking at the console shows a lot of sleep wake failures, like it broke the limit in Google Chrome and iStat for how many times it tried to wakeup. Then there were several crash logs, all Adobe except for a Windows Server one. See attached.
4. Photoshop is throwing a fit; I was using CC 2018 and it was complaining about a driver issue, but I recently realized 2018 isn't even supported on Catalina. So no issue here, but I am including for later in the post.

So then I wiped the drive and did a fresh install and update. All things were fine, until I started to install some of the programs, notably iStat and Photoshop:

1. The moment I opened iStat, I saw the triangular artifacts appear on the screen.
2. This is where I realized CC 2018 is not supported, so I installed CC 2020 instead. Never actually ran it...see next point
3. Machine started locking up, everything just froze; similar CPU 2 Caller Errors

I then accepted that Either the GPU or some of the parts are either not good/really compatible. I put all the stock parts in and did a OS Reinstall followed by Migration Assistant.

1. iStat still uses reports hight GPU VRAM usage... not really worried here...
2. haven't seen any artifacts yet.
3. No Shutdowns...yet?
4. Photoshop CC 2020 is throwing an absolute fit. this was a new install after I uninstalled CC 2018. Literally can't create a new document and it flashes like crazy after the error message appears. But this is like the bottom of the barrel compared to 2 and 3 which are currently not present.

SO, WHAT IS THE PROBLEM? I think it's safe to say the system itself is fine, so it must be the parts. I have heard of the Sintech adapter causing Hibernation problems in the past, so its a suspect but I have read that it was resolved in later models. But then there is the matter of the used CPU and RAM (The RAM of which is barely suspect). The system is not thermal throttling, as good paste was used, no fan software was utilized, and no fans were ever heard.

 

[mj_]

I honestly don't see how you came to the conclusion that this might be GPU-related. Yes, it might seem to be at first glance, but since your issues all but disappeared after you replaced pretty much everything except for the GPU it's quite clear that this can't possibly be GPU-related.

Based on the information available to me I would suspect the Sintech adapter. These adapters, whether Sintech or not, are notorious for causing all different kinds of problems, from sleep wake crashes to random freezes and lockups. If I were you I would try reinstalling everything except for the Sintech adapter and 1TB NVMe SSD, and try running the OS from the SATA SSD. It should still give you respectable and more than adequate performance compared to the spinning disk drive, and you might be able to eliminate the Sintech adapter from your list of suspects if the glitches return.

In other news, your Photoshop problems are most likely related to a profile issue and not hardware.

 

[KingCornWallis]

I honestly don't see how you came to the conclusion that this might be GPU-related. Yes, it might seem to be at first glance, but since your issues all but disappeared after you replaced pretty much everything except for the GPU it's quite clear that this can't possibly be GPU-related.

Based on the information available to me I would suspect the Sintech adapter. These adapters, whether Sintech or not, are notorious for causing all different kinds of problems, from sleep wake crashes to random freezes and lockups. If I were you I would try reinstalling everything except for the Sintech adapter and 1TB NVMe SSD, and try running the OS from the SATA SSD. It should still give you respectable and more than adequate performance compared to the spinning disk drive, and you might be able to eliminate the Sintech adapter from your list of suspects if the glitches return.

In other news, your Photoshop problems are most likely related to a profile issue and not hardware.

Hey, this is the 3rd site I have posted my issue to, and at this point I was definitely leaning towards the GPU not being the problem. But of course, remnants of my original posts where I concluded GPU issues remain.

Anyhow, you are correct! I have taken out that miserable Sintech Adapter and lo and behold all problems disappeared. So instead of using the top of the line PC SSD, I have shelled out for an expensive OWC version. Won't be any problems after this. Thank you!

 

[profcutter]

Just so you know, the OWC drive is just a normal NVME with an adaptor already attached. If you really want to avoid problems, you should look for a real apple drive on eBay.

 

[KingCornWallis]

Just so you know, the OWC drive is just a normal NVME with an adaptor already attached. If you really want to avoid problems, you should look for a real apple drive on eBay.

Normal NVMe: I would say it's far from normal. A normal NVMe drive used in a Mac requires manual Trim Enabling to maintain performance, this one does not. A normal NVMe drive also never guarantees out of the box compatibility with Macs (like the 970 Evo Plus that requires a firmware update to work at all)
Adapter Already Attached: I do hope you are referring to the drive as having the Apple proprietary pinout directly integrated to the PCB (the only of its kind), and not like a Feather Fledgling drive that is clearly just an off brand NVMe drive with an M.2 adapter attached to it.

Apple Stock Blades on eBay are slightly slower, much less power efficient, equally as (or more) expensive, used, and without a 5 year warranty. Additionally, it will likely be hard to distinguish between Apple's older SSD's, and the new ones with the Samsung UBX controller.

 

[profcutter]

If you read the thread on the MacBook pro page, you’ll see that the OWC drives have the same hibernation problems as generic drives do.

 

[KingCornWallis]

If you read the thread on the MacBook pro page, you’ll see that the OWC drives have the same hibernation problems as generic drives do.

Dang, what a fool I was. I just read so many advocates of the drive crapping on using NVMe drives with adapters. Never gave them any credit until my issues. But truth be told, the OWC drives are not that special. Just googled OWC hibernation and sure enough, its there.

 

[profcutter]

Yeah, the owc package has some good marketing behind it, but at the end of the day, it suffers the same problems, which leads folks to believe it actually is just a generic drive with a built-in adapter (probably soldered but still). The whole 3rd party NVME thing is hit or miss. I have one in my MacBook Pro, it works but it has some issues (it hibernates just fine). I was hoping to swap the drive for a Samsung one, but all the 2TB drives have shot up in price. If I had to do it again, I’d probably try to find a 2TB Apple drive, but they’re hard to find for a reasonable price.

 

[KingCornWallis]

Yeah, the owc package has some good marketing behind it, but at the end of the day, it suffers the same problems, which leads folks to believe it actually is just a generic drive with a built-in adapter (probably soldered but still). The whole 3rd party NVME thing is hit or miss. I have one in my MacBook Pro, it works but it has some issues (it hibernates just fine). I was hoping to swap the drive for a Samsung one, but all the 2TB drives have shot up in price. If I had to do it again, I’d probably try to find a 2TB Apple drive, but they’re hard to find for a reasonable price.

Well I will watch my OWC SSD carefully, I would say as long it doesn't CRASH like my SX8200 Pro + Sintech we should be golden. I can still sleep easy knowing there is the generous warranty though.