LiquidCrystal
Liquid Crystal Library for Arduino higher performance
License as per standard Creative Commons for Arduino libraries
Has been submitted as Pull request on Arduino arduino/Arduino#4550
Sorts some bugs with chip handlling, so delaying 100 us between each nibble of an 8 bit write when should be 1 us. Other fixes to get the delay times between commands to actually NOT block operation and reduce delays to sensible level of 40 us.
If you have a slower display there is an extra method to extend LCD command delay time to any value between 40 and 250 us.
See timings.txt which details tests and performance increase.
Some scope shot images in images folder, for differences.
Installation
Copy LiquidCrystal.h and LiquidCrystal.cpp to your Arduino/Libraries/LiquidCrystal folder
Restart Arduino IDE and recompile your sketch and restest.