Samsung 850 Evo ssd slow speed in Mac

[Tomkat9]

I've had a Samsung 850 Evo 250gb ssd for about 4 months now. When I first installed it was running great, but now my read/write speed is 205mb/s and 267mb/s. I'm on a 2010 MacBook Pro and still have 140gb free on the drive. What's causing it to slow down so much?

 

[BadAsAl]

2010 MacBook Pro had Sata II interfaces at 3Gb/s. The max read/write is not that far off your numbers.
What OSX are you using? Look into enabling TRIM on that SSD.
Run disk utility and repair the disk.
Run malwarebytes for Mac.
Make sure you have more than 10% free space.

 

[Tomkat9]

2010 MacBook Pro had Sata II interfaces at 3Gb/s. The max read/write is not that far off your numbers.
What OSX are you using? Look into enabling TRIM on that SSD.
Run disk utility and repair the disk.
Run malwarebytes for Mac.
Make sure you have more than 10% free space.

So is it possible to upgrade to a SATA III cable so that I can use the full speed of the ssd? I'm on Yosemite. I've heard some bad things about enabling TRIM and that it could erase your disk. Is this true? Thanks for the response

 

[BadAsAl]

Unfortunately no possibly to upgrade as it is built into the Logic Board.
TRIM for third party SSD's is now enabled by Apple (since Yosemite) and can be turned on using the command "sudo trimforce enable" from terminal.
I have only heard of bad things happening with TRIM on third party SSD's before Apple enabled it. You had to bypass their core security to enable it before and that did cause issues if you did not disable it before updating the system. I have not heard any bad things about it since it was enabled by Apple.