660P 2tb on late 2013 Macbook - 380MBs Write and 397MBs Read - very slow

[TManl]

I have installed the above drive but getting really slow speeds compared to the original SSD. The instructions to ugrade firmware fro Majave don't work as disk utility will not load the iso.

What else can I do to get the expected speeds?

[AlHill · Accepted solution]

You should contact apple support for help with your mac.

Doc

[TManl]

Turns out it is showing as having a lane width of 1 on my MacBook instead of x4. I am returning.