Mac is running super slow / beachballing

Welcome to the Apple Support Communities.

The reason your iMac is slow is due to the 5400-rpm hard drive. While this hard drive found in your Mac is perfectly suited to light tasks, such as email, web browsing, etc., for more advanced tasks, and for users who want the maximum performance from their Mac, this hard drive does have its limitations. Luckily, you can use an external SSD as your startup disk to run macOS and all your data from that. It will make your Mac 10 to 30 times faster for storage, and in turn, make your entire Mac system much faster. For more info, instructions, and what external SSD to buy, please see: How to Setup and Use an External SSD as your Startup Disk on a Desktop Mac - Apple Community.

Another option is to replace this Mac with a new Apple Silicon Mac: Mac - Apple. If you go this route, it is generally recommended that you purchase 16GB of Memory with the largest SSD that you can afford. You can also use Apple Trade-In to get credit towards a new Mac: Apple Trade In - Apple.

Jack

Newer systems have higher demands on the machine. Also with limited memory it's beneficial for performance to boot more frequently, like every 2 days or more, clearing out temporary system and application cache and swap files.

Jack-19's recommendation of getting an external SSD, cloning your system to it with Carbon Copy Cloner , booting and running from it is a very good way to speed up boot, application launch and document opening and saving times. Once a file is open then it becomes memory dependent for processing. Since you can't increase the amount of memory rebooting more frequently will help.

SReevo wrote:

Jack thanks for helping, something I don't understand tho, when I bought this Mac it was not an issue, this implies there has been a change which has caused this to happen ?

Your hard drive is performing a little slower than what it should be, but even brand new, that's the limitation.

Jack