I bought this CD in addition to the already present disc, and new performances on my PC. Mounted on a MSI GE70, I must say that this is the day and night, in about fifteen seconds the PC starts and I can start working. Installing W8.1 only took about twenty minutes. The 64 GB is enough to install Windows, the updates, and Office 2013. For the rest I have installed on another hard drive. Copies speeds are top! Easy installation but be careful not provided screws.