upgraded M2 on MBA 2017 - now getting slower

[z2000]

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]

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.

Why Solid-State Drives Slow Down As You Fill Them Up

The benchmarks are clear: Solid-state drives slow down as you fill them up.

www.howtogeek.com

 

[z2000]

around 50% usage. APFS format, I believe TRIM enabled. I only use this SSD some months with Mojave. I feel it is strange.

 

[z2000]

Solved. The problem is snitch adapter too close the slot. its may get some connection with ground. reinstall adapter and problem gone.

 

[Audit13]

With the early release of the small, green Sintech adapters, many users, including myself, had to use Kapton tape to prevent the metal Shield above the logic board's SSD slot from making contact with the pins on the Sintech.

When the adapter contacted the metal shield, the lane width dropped to x2 from x4.