Macbook Pro mid 2012
After installing MacOS Catelina, macbook pro 2012 became very slow, booting used to take about 2-3 mins & opening any application like chrome or Office use to take ages. Sleep/wake up was also like very very slow. After replacing WD Green SSD, restore installed Yosemite and it was damn superfast. Later I upgraded to Catelina. There was some reduction in speed (as Catelina is heavy on resources) but slowness was very minimal. My life has become lot more easy after installing this SSD. I am also about to do RAM upgrade to 16 GB (2x8gb) and that will be like booster dose. SSD upgrade is must for macbook Pro 2012 in 2020 to keep it up and running on Catelina.