I have reviewed the posts regarding the MP600 write speed issues and I seem to be experiencing the exact same issue on my M2 Mp510.
When I first got the drive, I consistently got the same speeds as per the specifications of the drive. I still have the same Win10 install which is around 1 year old.
Spec:
i7-8700k @ Stock
16GB (2x8gb) Corsair Vengeance 3000mhz
Gigabyte Z390M Gaming
Corsair MP510 960GB (362GB Free / 40c under load)
Things done/checked:
TRIM Enabled (also ran Optimize-Volume on the drive)
Updated Motherboard drivers
Updated MP510 firmware via Toolbox
Updated Motherboard BIOS to latest
Left computer off so that the drive cooled down, then tried ATTO again when drive was cooler
I'm stumped now and it looks identical to the issues the MP600 users are having. Any ideas?