Raspbian is a Linux-based operating system optimized for the Raspberry Pi, a low power, inexpensive mini-computer with a 700 MHz ARM11 processor. Up until recently, the folks behind the little computer had recommended using Debian Linux for an operating system. But benchmarks show Raspbian to be up to 40 percent faster at some tasks.
That’s because Raspbian is basically Debian optimized to take advantage of the features of the Raspberry Pi’s processor. That includes support for the ARMv6 instruction set and for hard float math operations.