Thumb instructions are the same speed, but can only perform a subset of what the ARM instruction set can; each instruction takes half the space. Thumb can be f

Thumb instructions are the same speed, but can only perform a subset of what the ARM instruction set can; each instruction takes half the space. Thumb can be faster if it eliminates cache overflows, but can also be a lot slower if faster ARM instructions have to be emulated with Thumb equivalents.