How i can boost my ram on iMac 21,5 late 2015

2015 21.5" iMacs have soldered in RAM therefore the RAM is NOT upgradeable. If you need more RAM, then you will need to replace the computer. Apple has been very forthcoming in advising users that RAM on 2012-current 21.5" iMacs is not users upgradeable. However, if you bought on price and bought one with a 1TB hard drive that is the primary bottleneck on your computer. What you can do is buy an external USB 3 SSD and then clone your internal HD to the SSD using either SuperDuper! or Carbon Copy Cloner and then use the SSD as your primary drive and use the internal drive as additional storage.

I second the recommendation to add the external drive. That said, since you can not realistically add more RAM, what you want to do is to use it in such a way as to not overload it. To that end, I offer the following suggestions. They are “maintenance” steps which are often ignored by many people.

·      It is important to occasionally restart a Mac. Ideally, once a week or more often. This does some system cleaning.

·      Regularly clearing the history of your browsers can help as all the data is stored in RAM. Clearing frees up RAM for system use. The Chrome browser uses a lot more RAM than other browsers do, so you may not want to use it.

·      Some people seldom empty their trash. If you haven’t, then do so. Also empty your email trash.

·      Some programs use a lot of RAM. (Like many Adobe apps and games.) When using them, close any other apps not being used.

·      Doing a restart in the safe mode can clear a number of problems. This is done by holding down the shift key at start up. This process can take up to ten minutes while the computer is doing its maintenance and cleans the cache. You may then restart normally.

·      Last, and most important, you should remove any and all Mac cleaner and antivirus programs. They will cause problems and will significantly slow your computer.

I hope these suggestions are helpful and enable you to speed up your computer a bit more.