Steam's Big Picture beta arrived earlier this week, but there was something else hidden in the files. Luckily, a couple of Redditors discovered the pretty big secret, as Steam now allows for multiple installation folder for the games. A bit of work is needed to pull it off, but it is well worth the effort.
There are some utilities available that do something similar, but this is the first time multiple installation folders have been built into Steam. What you need to do is create a new shortcut for the Steam.exe, but at the end of it add either -dev or -console, like so: "F:\Steam\Steam.exe -dev". Some Reddit comments also claim that -dev adds to the startup time for Steam, but either method will work.
Once that addition has been added and Steam starts, there should be a new "Console" tab up top. Click on that and at the bottom is a text entry box, which is where you type "install_folder_ui". A new window pops up that lets you add in new installation folders for your Steam games. Close that window and then you will be able to install nearly any Steam game to another hard drive, which is ideal for SSD users. Not every Steam game is able to install to a different drive, but a good number do. That's all there is to it, so enjoy!