Upgrading Memory on iMac

Sadly, Apple didn't design this series with upgradable RAM as you can see here both the RAM and the CPU are soldered to the logic board

These RAM chips are quite hard to desolder/solder without having the needed tools which are quite expensive. If you make a mistake thats the end of the logic board.

Think of it this way... Your on the high wire platform at the circus and you need to cross it and you've never even practiced are you willing to chance it?

Sometimes the job is beyond what we possess, it might be a physical limitation or it could be a the needed practice to acquire it. Here we have both the tools and the skills and we still need access to the replacement RAM chips. All in all this is quite an expensive proposition and given the value of the system and the risks I think its better to locate a newer system (series) new or used which at least has replaceable SO-DIMM support and maybe even a CPU.