Hello, recently I noticed that my new PC(Windows 8 ) compiles slower than my old laptop(Lubuntu Linux). So looking into compile process I found that Arduino IDE recompiles every single library. I spent a day finding and testing all sorts of solutions. The one that actually worked was the one I found myself, so I decided to share it with you. What helped was reinstalling Arduino IDE to "C:\Arduino" and moving sketches folder to "C:\ArduinoSketches".
If this solution is already posted you can remove this.