How much total new RAM can I add to a 2010 iMac that originally had 4G of RAM and now has 8 Gig with 2G in each of the four slots. Also -- by adding more RAM will my computer be faster again?

The free Malwarebytes may take care of it...

https://www.malwarebytes.com/mac/

Or...

EtreCheck is a simple little diagnostic tool to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac. It will not display any personal info.

https://www.etrecheck.com/

Pastebin is a good place to paste the whole report if you capture the URL while there…

https://pastebin.com/

Workable but harder for me to work with...the Note tool on the bottom of this editor's toolbar, as shown in the image, to copy and paste the output from EtreCheck. In a Reply before you click post, look for this to add longer texts..

In that generation of Macs, more RAM is nice, but an SSD is what will make them really perform well.

I had a Late 2009 27" i7 iMac. I put 32GB in it. It was faster switching between apps, because I was not longer paging code and data in-and-out of memory.

BUT WHAT MADE IT REALLY Perform well, was when I replaced the DVD with an SSD. The DVD to SSD conversion kit I got from OWC <http://MacSales.com>. That Mac performed very well run up until a building wide power failure took it out and it would no longer power up (that was last August; just short of its 10 year anniversary).

16MB max -- https://support.apple.com/en-us/HT201191#2

Greg Weir wrote:

16MB max -- https://support.apple.com/en-us/HT201191#2

That was back in 2010 when 8GB RAM was not available. Apple does not update their documentation to reflect new capabilities.

A Mid 2010 27" iMac can have up to 32GB installed. Whether it would be faster would depend on why it's slow.

It will likely be faster with more RAM.

Any luck yet?