I am going to upgrade a250gb hhd to an ssd in a Dell Optiplex 790. I am debating on whether to upgrade the ssd for faster boot times only, where I would buy an ssd with a capacity of around 120gb, or for general use, in which I would buy a larger capacity like a 240gb or 500gb. I also am wondering on how I would transfer my os from the HHD to my SSD as when I buy the optiplex it would come with windows 10 installed on the HHD. Any help would be appreiciated. Thanks!