Yeah 200mS is an eternity to a microcontroller. That was something that took some getting used to when I first started working with microcontrollers, just how blindingly fast they are. Think about it this way, even running at a very slow clock speed of 1MHz most microcontrollers will be running something around 100,000 C instructions during each of those 200mS, surely whatever calculations you're doing are not going to require anywhere near 100,000 instructions. 1MHz is very slow, the bog standard Arduino runs at 16MHz, that's millions of instructions per second.