upgraded M2 on MBA 2017 - now getting slower

z2000

macrumors newbie
Original poster
Jun 3, 2019
10
0
Rotterdam
I have samsung 970EVO with adapter on my MBA 2017, running Mojave. in the beginning, I use blackmagic disk speed test to get 1.3/1.5Kb ( I understand that is limited by Apple) however, today I tested only get 735Mb. the OS is 10.14.6 now.

What caused it? Does it issue from MacOS or from the Samsung 970?
 

flaubert

macrumors regular
Jun 16, 2015
231
34
Portland, Oregon
How full is your disk, what format is it in (HFS+ versus APFS) and have you enabled TRIM support? As your disk fills up, the SSD has to do more to manage the blocks: without TRIM enabled it doesn't truly know which blocks are still in use, and which are free, so it has to coalesce the blocks that it knows are free to erase them, and then write your data. Net result is a drive that slows down.

 
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z2000

macrumors newbie
Original poster
Jun 3, 2019
10
0
Rotterdam
around 50% usage. APFS format, I believe TRIM enabled. I only use this SSD some months with Mojave. I feel it is strange.