Macbook Air 13" Mid-2012 Slow SSD Speeds

[macnoob2525]

I have a Macbook Air 13" Mid 2012 with the specs listed below. Using Black Magic v3.0, I get write speeds of 235MB/s and read speeds of 453MB/s. After doing some research, this write speed seems slow. I have been getting these speeds since I first purchased the laptop in 2012. Last week I purchased a Samsung 850 EVO 256GB M.2 SSD drive and a M.2 Macbook Air mid-2012 adapter. After installing the drive with the adapter I still get almost exactly the same speeds as the 128gb drive. I tried performing a SMC reset, as well as using a clean install of Mac OS Sierra, but still get the same slow speeds. Would purchasing a native SSD, like the Transcend possibly help?

It's also worth noting that I don't actually feel the "slowness" of the computer, probably because I have always gotten write speeds of around 235MB/s.

Any help would be appreciated, thanks!

The name of the M.2 adapter I used is: Generic M.2 NGFF SSD to 18+8pin SSD Adapter for 2012 MacBook Air A1465 A1466

Specs
Macbook Air 13" Mid-2012
SSD: 128gb
Processor: 1.8GHz i5
RAM: 8GB of Ram

 

[stockscalper]

You're probably limited by the bus speed on the computer.

 

[chabig]

I have a Macbook Air 13" Mid 2012 with the specs listed below. Using Black Magic v3.0, I get write speeds of 235MB/s and read speeds of 453MB/s.

I think those seem pretty fast, especially for a 2012 machine. For comparison, my 2013 11" Air gets about 300MB/s and 480MB/s.