I was having the same problems with SDSSDP128G slow write speeds. The machine would often hang for seconds at a time.
Runing “atop” it would say the drive is 100% busy with only a few dozen write operations queued.
I’ve been running “fstrim” regularly to TRIM unused blocks, but it hasn’t helped as far as I can tell.
I followed the Secure Erase instructions and now speeds are back to normal (and I’ve lost some SSD life as a consequence).
I’m a Linux user and the instructions that worked for me are here:
https://skrilnetz.net/the-truth-about-how-to-securely-erase-a-solid-state-drive-ssd/
In particular, to get the drive to be “not frozen”, I had to do the shown “echo -n mem” trick to drop into sleep and then wake up again.
(See the summary, below.) Then the other two commands that set the password and did a security erase worked no problem.
SInce this was my root drive, I copied all the data off then booted Ubuntu Linux off a USB key and used that to erase my “sda” drive,
then I re-partitioned the drive and copied all the data back, set the GRUB bootloaders, and rebooted. No more hanging! Summary:
# echo -n mem \> /sys/power/state
# hdparm --user-master u --security-set-pass PASS /dev/sdx
# hdparm --user-master u --security-erase PASS /dev/sdx
