My sister has a 2010 13" MBP model designation 7,1. This is a unique model in that it can use 16 GB RAM instead of the 8 GB that is standard for this MBP line. Right now her computer is nearly unusable it is so slow. I checked her system profile and she only has 4 GB RAM and is running Sierra. Also, the computer has a standard hard drive - not an SSD. I know that 4 GB is generally considered completely inadequate for the current MacOS releases. My question is will going to 8 GB be enough to make the machine usable? Would 16 GB make much difference over 8? I have a 2010 15" MBP with 8 GB, but it has an SSD which made a big difference in it's performance. Will the RAM upgrade to my sister's MBP be enough? Thanks!