The Arduino platform has been under pressure for a while now. The project that enabled embedded computing power for all makers out there has been falling behind on the CPU side. Still, it has maintained its position as one of the easiest platforms to develop for available.
All this changes with the Arduino DUE board. The board changes much of what we know about Arduinos. The CPU is an ARM clocked at 84MHz, the signal level 3.3V. 95kB of RAM with half a megabyte of FLASH means that the software run is less limited by size.
Released the 22nd last month, you should be able to get your hands on the hardware through your usual supplier.