[Mtn_Biker]

I'm currently using a MBP 2013 with 16GB driving a 4K monitor. I'm thinking to a 27" iMac with 2TB fusion drive and continue to use the 4K monitor when I need the real estate.

I tend to have a lot of Safari tabs at times—say 20, Mail, Evernote, TextMate, Console and a few other apps open. Photos app is driving me to upgrade: 20 or 30 seconds to delete a photo, for example. First time posting here and don't see an way to photo a screen shot, so here's what Activity Monitor shows in words with 20 apps open, (numbers rounded off):
Memory Used: 12GB
Cached Files: 4GB
Swap Used: 4GB
App Memory: 8GB
Wired Memory: 2GB
Compressed: 2GB

The numbers a couple of hours later are similar except Swap is up to 7GB and compressed 600MB.

Will I benefit from 16GB?

I usually buy refurbs and 8GB is much more common and of course cheaper. Thanks for any info. I don't do any gaming, no video editing.

[Mtn_Biker]

OP here. It's been a while since I've dealt with an iMac and forgot you could add memory; so I'll order 8GB and probably upgrade to 16GB unless I find out more would help. (Usual after posting thoughts on what to search for revealed upgradeability)

PS I may end up ordering a new one because I prefer a numeric keypad and that seems to be rare in the refurbs.

[Trees]

Getting as much RAM as possible is typically a good idea. Requires less swap or compression. SSDs are fast, so the swap may not be as noticeable as with a spinning HDD, but still preferable to keep as much as possible in RAM.