Without going much into detail, TRIM is an operation system level command which essentially provides that a SSD‘s flash chips face fewer erase and rewrite cycles when data is deleted and the available space newly used.
This maintains a SSD‘s write speed over time and also reduces wear caused by write operations.
When your SSD‘s write performance slows down like yours, it could be that (1) your drive is exhausted (but doubtful after 1.5 years, and the Samsung is a great drive) or that (2) exactly TRIM is not active. Note that macOS by default deactivates TRIM on non-Apple drives, so this is a likely case here.
To test for (1), download the free (for a trial period) app DriveDx, run it and post a screenshot. High numbers for reallocated sectors or high drive write values would indicate an exhausted SSD.
To test for (2), click the Apple logo on top left corner and open ‚about this mac‘, then click on ‚system information‘ and there select ‚SATA‘. You’ll find an entry for TRIM enabled, and most likely the value is ‚no‘.
If that is the case, time to activate TRIM!
First, and if you have not already done, create a backup!
Then, open the ‚Terminal‘ utility in the ‚programs->utilities‘ folder and enter the following command:
It’ll ask for your admin password and then whether you really want to do that. Confirm, and then TRIM will be activated and eventually, after a short time, your machine will reboot.
Check again under system information whether TRIM now is activated. If so, that’s all you have to do.
Already after a few minutes with TRIM you should see a great improvement in SSD performance.
Good luck!
Magnus