Question: Q: RAM Upgrade

There should be a RAM door in the back for upgrading your RAM, more information on how to upgrade your RAM in your iMac can be found here. Hope this helps.

Apple buys RAM from various vendors. iMacs are very sensitive to quality RAM and most experienced users on these forums use either Crucial.com or Macsales.com RAM. Both vendors provide high quality products, lifetime warranties on their RAM, offer great service and sell for very competitive prices. In short, there is no reason to not choose one of these vendors.

Most users here would suggest crucial.com or https://www.macsales.com/

Possibly, but it's best to buy online from either Crucial.com or Macsales.com, you would need tocall your local AASP to see if they sell RAM.

Also, when replying to a question on these forums, please click reply in the message you are replying to, that way we can tell who you are talking to.

Apple gets the RAM they install at time of manufacture from several makers including Micron (Crucial's parent), Elpida, and Hynix. For more than a decade I have bought all my expansion Mac RAM exclusively from Other World Computing. Crucial is the other trusted source for long-serving users here.

This is the OWC RAM listing for your model:

https://eshop.macsales.com/shop/memory/iMac/Retina-5K2015/DDR3L

Crucial has a lookup function to find their product for your computer. Start at crucual.com

Avoid RAM sold on auction sites, and any RAM identified as "value RAM." Macs can be picky about RAM. Kingston and Corsair have two quality tiers, and the lower tier stuff is not happy in modern Macs. Problem is, resellers seldom tell you you are getting the cheaper version. That is why I use either Crucial or OWC for me. Both sell only top-tier RAM that is Mac-tested.

It’s hit and miss most times, because not all AASP’s like Best Buy or Fry’s carry RAM for all the different models. Besides in most cases, they charge higher prices than Crucial and OWC.

Your welcome.