Xcode DerivedData -> RAMDisk

gistfile1.md

Make Xcode use RAMDisk:

• Create a new disk called RAMDisk with 2GB of disk space
  (usually pretty enough, unless you are compiling a lot of projects)
  (the number in the last piece is number of megabytes you want to use for your disk multiplied by 2048, in this case it's 2048 * 2048 = 4194304.

diskutil erasevolume HFS+ "RAMDisk" `hdiutil attach -nomount ram://4194304`

• Goto: Xcode -> Settings -> Locations
• Change DerivedData to use Custom in the dropdown
• Specify /Volumes/RAMDisk
• ???
• Profit