Bests & Worsts Reviews from Amazon

I have a late 2009 MacBook (the white polycarbonate one). It was performing unbearably slowly-- app switching and launching, booting, and even shutting down frequently took minutes. Scrolling in any app that accesses a lot of data (Evernote, even 1Password) was often very laggy. This was true even when I had large amounts of free/inactive memory. It was very frustrating, and I was almost ready to buy a new computer. However, I could see very high disk activity in the Activity Monitor during the slow periods and figured the bottleneck was probably my hard drive... so I went ahead and bought the Samsung 840 Evo and upgraded my RAM to 8 GB (Crucial 8 GB Kit (4 GB x 2) DDR3 1066 MT/s (PC3-8500) CL7 SODIMM 204-Pin for Mac (CT2C4G3S1067M )). Best computer decision of my life; the performance problems evaporated when I put in the Evo and the new RAM. Apps launch in seconds, no laggy scrolling, and I haven't hit the limit in terms of the numbers of things I can have open at once. Highly recommended. P.S. Make sure you have an appropriate screwdriver (Wiha 96100 Phillips Screwdriver with Precision Handle, 00 x 40mm) and either a USB to SATA cable or a 2.5" hard drive enclosure. The screwdriver is needed to remove the bottom of the MacBook and to release the hard drive; the cable or enclosure is needed to connect the drive to your computer so you can clone your current drive before making the switch. Other screwdrivers might also work. Some articles I read suggested that a "T6" screwdriver was needed, but it wasn't for my MacBook model; can't speak about others.