My 2011 Mac Mini, OS X El Capitan 10.11.6 up-to-date, wifi speed good, 8GB memory, of which 3-5 in use, often slows down with rainbow whirligig. This happens when I switch from wind to window or app to app quickly.
Mac mini, OS X El Capitan (10.11.6), 8GB memory
Other system specifications, and resource usage may indicate the cause
of this slow-down at those times; the Console log files may be helpful if
you use them according to exact time of each occurrence, for details.
Disk Utility can also be helpful to compare certain items in the system.
Even to simply look into the overall picture by use of a system report
generating tool such a Etrecheck http://etrecheck.com/#about may be
one way to have a report and also post a copy into these discussions.
I'd suspect part of the lag may be due to the amount of saved content
on the computer storage drive; if the content is becoming too much
the resulting lag may be due to temporary swap files or virtual memory.
You may need to archive some of your user-generated content to external
hard drive storage for later retrieval, and then remove the original from HDD.
The amount of unused capacity of the boot drive, aka "free space" can be
of major importance since the Mac system will use that capacity to run.
In addition to more memory (RAM) installed, a larger hard drive could help.
Or less accumulation in the hard drive where the system lives.
Good luck! 🙂
I suspect a failing HD since it happens when you read/write to the drive. It is slow because data has to be repeatedly read/write from the drive to get a good read/write.
- Try resetting the SMC and NVRAM/PRAM
Intel-based Macs: Resetting the System Management Controller (SMC)
https://support.apple.com/en-us/HT201295
About NVRAM and PRAM
https://support.apple.com/en-us/HT204063
- Try starting in Safe Mode
OS X: What is Safe Boot, Safe Mode?
https://support.apple.com/en-us/HT201262
- Boot to Recovery and repair the startup disk
OS X: About OS X Recovery - Apple Support
https://support.apple.com/en-us/HT201314
Also note in Disk Utility if the SMART status is listed as verified.
- If it is repairable reinstall the OSX
How to reinstall OS X on your Mac - Apple Support
https://support.apple.com/en-us/HT204904
- If you do not have a backup use disk utility to restore the internal disk to an external disk so you can try to recover data.
Then format the startup disk and do a fresh install of OSX
Mac Mini sometimes slow.
