I am using STM32F427ZG and have a query about the CMSIS FIR Filter functions. We require highest possible speed in a 16 bit environment. I have been comparing speeds for the q15,q31 and float32 FIR filters. The STM32F427 has floating point hardware, but I had hoped the q15 implementation of the filters would be faster than the q31 or float32 due to the SIMD instructions. However I am finding that they are all very much the same speed, if anything the float 32 is slightly faster, This applies at all levels of optimisation. Can anyone advise me please?