iMac 2017 4K Retina: Kernel panics, slow; external SSD?

You did not have a hardware issue at the time of the test. Don't jump to the external SSD solution just yet. It could slow you more. How about a serving of data from your report?

Your current drive scores:

Performance:

System Load: 1.58 (1 min ago) 2.04 (5 min ago) 1.71 (15 min ago)

Nominal I/O usage: 9.67 MB/s

File system: 22.39 seconds

Write speed: 630 MB/s

Read speed: 1181 MB/s

The speed metrics are within the expected range for an Apple Fusion drive in that iMac model, and a 22-second "File System" score suggests your drive is healthy. All SSDs are far more costly this year due to data center demand, and even the least expensive external SSD boot volume option can do only 400 MB/sec on its best day ever. That would be a downgrade compared to your current performance.

Your RAM was not stressed at the time of testing.

You are suffering self-inflicted software issues.

— antivirus: completely remove ClamXav, and change MalWarebytes to run in manual mode only

— Divx: Look at the date in this:

[Loaded] com.divx.agent.postinstall.plist (Not signed - installed 2012-03-11)

Its five year OLDER than your computer. There is evidence that old versions of Divx can slow Mac performance. If you use it update it. If not, dump it.

— this is a BIG issue:

VPNs:

[Loaded] PacketTunnel - /Applications/VPN Unlimited.app

[Loaded] WireguardPacketTunnel - /Applications/VPN Unlimited.app

[Loaded] XrayPacketTunnel - /Applications/VPN Unlimited.app

One client-side VPN is very bad; three are the basis for a disaster movie script. You need NONE. Those alone could be the cause of your slowness. Please don't fall for fear marketing.

Send out the needed eviction notices, restart the computer, and run another test. There may be more issues lurking.

Based on your EtreCheck report, the kernel panics are not pointing to a traditional hardware panic such as memory corruption, CPU faults, or GPU hangs directly. These are “userspace watchdog timeout” panics, which typically occur when a critical macOS process becomes completely unresponsive for an extended period of time. On a 2017 Intel Mac, this commonly correlates with severe disk latency, failing storage hardware, GPU instability, corrupted macOS components, third-party kernel/system extensions, or excessive system resource exhaustion.

The two processes involved here are especially important:

logd timeout

The macOS logging subsystem stopped responding for over 120 seconds. This often indicates underlying storage I/O problems because logging continuously writes to disk. This can also occur from filesystem corruption, failing SSD/NVMe components, or severe OS-level hangs.

WindowServer timeout

The graphical interface subsystem froze. Common causes include GPU acceleration issues, external display problems, corrupted graphics settings, insufficient free storage, or runaway third-party software causing the UI to stall.

Okay, with that said, here are a few things you may want to check out:

Verify Available Storage

Ensure at least 15–20% free disk space is available on the internal SSD.

Run Disk Utility

Boot into macOS Recovery and run First Aid on all APFS containers and volumes.

Check SSD Health

Review SMART status and storage performance using any/all of the following:

• DriveDx
• smartmontools
• Apple Diagnostics

Test in Safe Mode

Booting into Safe Mode disables many third-party services and clears certain system caches. If performance improves or panics stop, third-party software is likely involved ... and, if that is the case you will want to carefully review any third-party software you have installed on your Mac.

Disconnect External Peripherals

Temporarily disconnect external monitors, docks, USB hubs, and storage devices to rule out GPU or I/O related hangs.

Check Activity Monitor

Look for processes consuming excessive CPU, RAM, or disk activity prior to freezes.

Hardware Considerations

If the system continues experiencing watchdog panics after software remediation, the internal SSD or logic board should be considered suspect, especially given the age of the hardware.

Allan Jones wrote:

Thanks for the follow-up, Gordy. Usually EtreCheck picks that stuff up. Normally the File System score is nearly to the 120-second "Stop the test, I want to get off!" point when that drive behavior is present. Oh well, more meat for the collective Knowledge Base here, and that's a good thing. I appreciate your seeing it through.

I've never had a 3.5-inch drive fail but have lost some 2.5" models due to mysterious maladies. They do not seem as robust as their bigger brothers. Apparently the minimalist thin-case design precludes using a 3.5-inch internal drive in 2012-2019 21.5-inch iMacs.

Yeah, that is an odd health report and I've personally analyzed a lot of them for my organization over the years. I am surprised by the drive speed reported in the EtreCheck report since it appears there are still 17K bad sectors pending reallocation.

Typically these 2.5" Hard Drives do not hold up as well as their 3.5" counterparts even when used in a Desktop system where they tend to have less jostling of the computer. This HD had 60K power on hours which is actually a lot for a 2.5" HD and that 60K power on hours exceeded the manufacturer's lifetime expectations as evidenced by the normalized values for that attribute where "Worst" is at the lowest value possible "1" & never meeting the Threshold of "0".

Life-span (aka "Old Age") attributes have a Threshold of "0" because they do not necessarily indicate immediate failure unlike the "Pre-Fail" attributes which have a Threshold of "1". SMART will trigger a Failing Status for the drive if the "Worst" drops to or below the Threshold. Since "Value" and "Worst" normalized values never drop lower than "1" the "Life-span" (aka "Old-Age) attributes will not trigger a failing status since they never got to the Threshold of "0".

ID   | NAME               | TYPE      | UPDATE     | RAW VALUE          | VALUE | THRESHOLD | WORST | LAST MODIFIED        | STATUS
 9    Power On Hours       Life-span    online         60,116                1        0         1        16/05/2026 13:14    1.0%  Warning     

Part of divx is still there. You should delete the User Launch Agent here:

~/Library/LaunchAgents/com.divx.agent.postinstall.plist

It appears it may also still have some divx files here as well (I would think it is Ok to delete that "DivXBrowserPlugin.plugin" folder since there may be other divx related files in there):

/Library/Internet Plug-Ins/DivXBrowserPlugin.plugin/Contents/Resources/extensions-installer

/Library/Internet Plug-Ins/DivXBrowserPlugin.plugin/Contents/Resources/DivXHTML5.safariextz

You may also want to delete these items noted in the CleanUp section of the EtreCheck report:

    ~/Library/LaunchAgents/com.hp.productresearch.plist

    /Library/LaunchDaemons/com.wyse.PocketCloud.plist

    ~/Library/LaunchAgents/com.valvesoftware.steamclean.plist

    ~/Library/LaunchAgents/com.hp.devicemonitor.plist

Hmmm. Can you clarify on what specific part of performance is poor? That may help with further diagnosis.

You do have a notable improvement in drives speed scores from the prior test. Much closer to max performance possible with that drive config: 900 MB/sec writes; 1400-1500 MB/sec reads.

My next suggestion would be to test with the external USB drive disconnected. Not a sure thing but I've encountered several matters here where an external drive caused some slowness.. It is not usually an issue with Seagates, but it is easy enough to check.

In case someone suggests it, adding RAM will not give you a noticeable a speed improvement at the keyboard., and the installation costs alone (needs a pro) are not financially feasible. The sealed-case computer must be virtually gutted to access the well-hidden RAM slots. You can spend a bundle uipgrading RAM and not sense one iota of improvement.

Thanks for the follow-up, Gordy. Usually EtreCheck picks that stuff up. Normally the File System score is nearly to the 120-second "Stop the test, I want to get off!" point when that drive behavior is present. Oh well, more meat for the collective Knowledge Base here, and that's a good thing. I appreciate your seeing it through.

I've never had a 3.5-inch drive fail but have lost some 2.5" models due to mysterious maladies. They do not seem as robust as their bigger brothers. Apparently the minimalist thin-case design precludes using a 3.5-inch internal drive in 2012-2019 21.5-inch iMacs.

Allan Jones wrote:

You did not have a hardware issue at the time of the test. Don't jump to the external SSD solution just yet. It could slow you more. How about a serving of data from your report?

Your current drive scores:

Performance:

System Load: 1.58 (1 min ago) 2.04 (5 min ago) 1.71 (15 min ago)

Nominal I/O usage: 9.67 MB/s

File system: 22.39 seconds

Write speed: 630 MB/s

Read speed: 1181 MB/s

The speed metrics are within the expected range for an Apple Fusion drive in that iMac model, and a 22-second "File System" score suggests your drive is healthy. All SSDs are far more costly this year due to data center demand, and even the least expensive external SSD boot volume option can do only 400 MB/sec on its best day ever. That would be a downgrade compared to your current performance.

Your RAM was not stressed at the time of testing.

You are suffering self-inflicted software issues.

— antivirus: completely remove ClamXav, and change MalWarebytes to run in manual mode only

— Divx: Look at the date in this:

[Loaded] com.divx.agent.postinstall.plist (Not signed - installed 2012-03-11)

Its five year OLDER than your computer. There is evidence that old versions of Divx can slow Mac performance. If you use it update it. If not, dump it.

— this is a BIG issue:

VPNs:

[Loaded] PacketTunnel - /Applications/VPN Unlimited.app

[Loaded] WireguardPacketTunnel - /Applications/VPN Unlimited.app

[Loaded] XrayPacketTunnel - /Applications/VPN Unlimited.app

One client-side VPN is very bad; three are the basis for a disaster movie script. You need NONE. Those alone could be the cause of your slowness. Please don't fall for fear marketing.

Send out the needed eviction notices, restart the computer, and run another test. There may be more issues lurking.

Why can't you restore your 2017 iMac, from your Time Machine?

Please, explain it to me!

But ,I may have overlooked ,something from that Etrecheck report?

I have the same 2017 iMac running Ventura, 1 TB Fusion drive, with no Beachballing,and, no frequent restarts with Kernel Panic?

"When my old 2017, iMac, running Ventura 13.7.8 ,get (Sluggish),and slow, I Reinstall, it from my Time Machine copy"

This is not true!...........I have ever reinstalling, my old 2017 iMac in this nine years!

I may have been lucky?

But, maybe it's about us using our heads?

You're very welcome! Thanks for providing the DriveDx results.