MAC Mini 2018 (8GB Ram 3GHz i5) dog slow for every day tasks with 3x4K Monitor

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I believe we need to proceed with an EtreCheck report. EtreCheck is a useful App to diagnose and identify issues, both hardware and software. It is trusted by many users. Please follow the steps outlined below:

1. Navigate to: https://etrecheck.com and get the free version of EtreCheckPro.
2. Download it. It is a free and trusted app. It is often recommended here on Apple Support Communities. 
3. Open EtreCheck, and before running the report, be sure to check “Allow full Drive Access” at the bottom of the EtreCheckPro window.
4. Run the report, and put it in a post, as seen here: https://discussions.apple.com/docs/DOC-250000211. We will then examine the report for issues in your Mac.

Jack

Sleep isn’t necessary. Check “Prevent…” in Energy Preferences and uncheck everything else except auto start on power fail. Then shut down, disconnect power from wall/strip socket and bring everything back up after 10 minutes. That should fix the wake issue.

As for performance, one or all of Chrome+Citrix+Outlook IMO is suspect. You can eliminate them all by testing individually, in pairs and finally as a trio. Good luck!

Sleep is all pain, no gain. For long absences, shut. Keep it disabled, it serves no purpose on later Macs.

Could you clarify 'dog slow'?

Are you seeing the beachball of doom? Is the user interface or graphics lagging? Is something else slow?

Also +1 for running Etrecheck and posting a result copy.

Not according to Apple. At the moment, your issue with wake is easily worked around and your performance issues can likely be isolated if not fixed. So I would focus on that. All the best!

👍

1) This is a strong suspect in your slowness:

Diagnostics Information (past 7-30 days):

2021-10-07 00:33:24 photoanalysisd High CPU Use (3 times)

It is an aggravating problem that has been around a while but can be managed. See this forum topic for useful tips:

https://apple.stackexchange.com/questions/310594/what-is-photoanalysisd-and-why-is-it-using-77-of-my-cpu

2) With only 8GB RAM you should try restarting your computer more often, like every 3-4 days, to clear out the deadwood:

System Software:

macOS Big Sur 11.6 (20G165)

Time since boot: About 8 days

3) You internal SSD is performing up to expectations so that is not an issue.

4) A 2018 Mini will handle up to 64 MB RAM. Normally I do not find RAM to the the issue in slow computer complaints but, in this case, yours was writing data to Virtual Memory in an amount equal to 25 percent of installed RAM; this is "Swap Used" in this part of the report:

Free RAM: 33 MB

Used RAM: 6.75 GB

Cached files: 1.22 GB

Available RAM: 1.25 GB

Swap Used: 1.96 GB:

That is a lot. Restarting more often will keep usually that from being an issue. However, run Etrecheck again a day after a restart and see if "Swap" is zero or at least under about 500MB. If it is higher, consider adding physical RAM.