Etrecheck report for Constant crashing

OWC RAM should be good. Always works for me.

The computer out of the box was slower than my late 2009...

As den.thed says, "Slow" is the glacial 3GB/sec 5400 RPM drive in a computer with a fast 6GB/sec drive bus. I can support your older iMac observation. Our 2011 21.5 inch entry-level iMac posts data transfer rates much faster than your 2019 posted.

Your 2019 iMac:

Performance:

System Load: 2.76 (1 min ago) 2.04 (5 min ago) 0.93 (15 min ago)

Nominal I/O speed: 6.00 MB/s

File system: 105.62 seconds

Write speed: 61 MB/s

Read speed: 62 MB/s

Our 2011 iMac:

Performance:

    System Load: 1.62 (1 min ago) 1.67 (5 min ago) 1.87 (15 min ago)

    Nominal I/O speed: 0.05 MB/s

    File system: 38.28 seconds

    Write speed:  112 MB/s

    Read speed:  91 MB/s

In 2011 Apple installed 7200 RPM 3.5-inch drives. From 2012 to 2019 they installed 5400 rpm 2.5-inch laptop drives. All were rated at half the computers's bus speed of 6GB/sec. You 2009 had a 3GB/sec bus but was probably a 7200 rpm model.

The USB3/ 6GB/sec SSD solution den.thed shows should post rates in the range of 400MB/sec based on other reports here. As you are comfortable opening the case (congrats, by the way!) you can replace the existing drive with an internal 6GB/sec 2.5-inch SSD and get rates of around 500MB/sec in an EtreCheck test.

There is conflicting information on adding a blade SSD to an iMac that shipped with a conventional hard drive. OWC info says their blade upgrade is not compatible unless the iMac shipped with an Apple Fusion drive or an Apple SSD. Worth checking with other vendors to see if this is more that an OWC limitation.

+1

The RAM is my concern as well. From what I can find, Apple would not ship that model with more than 32GB RAM pre-installed.

Yes, RAM vendors say that 64GB is possible, and I have more RAM in some of my Macs than Apple specs show. However, I've found that only applies to quality RAM. If Other World Computing or Crucial say it works, I trust them and would use their products. I would not attempt it with other brands/vendors.

Were this a 27-inch iMac, I'd tell you to simply remove one RAM module and test. I can't do that when the iMac is a sealed model.

RAM issues are a major cause of kernel panics, so I wonder what RAM brand used in the upgrade.

We know Crucial and OWC work. We also know that "value RAM" from Corsair and Kingston are troublesome. PNY, once the darling of us G-series PowerMac users, stopped being a viable option when Apple switched to Intel processors in 2006.

Did you order it with 64GB of RAM or did you DIY the RAM?

If you ordered it with 64GB or RAM you should have also up graded the 5400rpm HDD to an SSD.

If you replaced the RAM yourself, what RAM did you use and why didn't you replace the 5400rpm HDD with an SSD.

Yeah' those 5400rpm Hard Drives are slugs. As a test, get yourself an external USB-C SSD, install macOS on it and see if your iMac doesn't preform better while running from it. FWIW even a USB-A 3.0 external SSD would run faster than what is currently in the iMac.

👍 Allan.

FWIW I do trust PNY SSDs in Mac's. I've been using them in Mac's for close to 10 years and none of them have ever let me down.