MacOS – keep the OS as-is, on swapping SSD on compatible Macbooks

Sandisk/Marvell drives are about ~500MB/s write and Samsung drives are ~700MB/s write speed. Both have around 700MB/s read speeds.

It's important to note that while these are different, under regular use it's very unlikely that either will have any sort of performance implications. Benchmarks tell very little about day-to-day performance.

As long as you can confirm the laptop is indeed from mid-2012 (later models have the memory soldered in), then these specs should work for you with either a 13" or 15" laptop (Apple started soldering memory in 17" laptops after 2011):

• 204-pin
• PC3-12800 DDr3 1600 MHz type RAM

(Found at http://support.apple.com/kb/HT1270)

As far as hard drives go, I'd personally recommend a Crucial SSD, but yes, any solid state drive will work.

Hope this helps!