mid 2011 iMac beach ball

[JustUs35]

A family member has an iMac 12,1..21.5" mid 2011, 2.5 i5 with 4 GB of ram. Running High Sierra. The 500gb hard drive has 18gb free space.
When doing anything...opening programs, emails, downloading documents........The beach ball starts and stays spinning for quite a while. Especially in power point. Very frustrating.
I told them to clear out space on the HD to get to around 50gb free space and I would Install another 8gb of ram. We ran permissions but did not speed up the beach ball activity. I remember reading that OS X, High Sierra is hard on early processors...is this true? add more ram? Any other Thoughts? Thanks in advance for any replies.

 

[mikehalloran]

Replace that hard drive with a 1TB or larger SSD and add at least 8GB RAM. While you're in there, replace the NV RAM battery with a CR2032. Parts — well under $200. Labor $75 or $27 for a tool kit.

It won't run like a 2017 or later but you won't believe it's the same machine—the difference will be that great.