You must baseline and reset your System Management Controller (SMC) and your Parameter RAM (PRAM) device. Both of these components are minor cogs in the wheel, but once they get corrupted, things slow down. If your Macbook slow after sierra update, you should reset SMC and PRam. This is what you do:
SMC Reset on MacBook, MacBook Pro or MacBook Air:
You do not risk the loss of data or any other catastrophic event, so let out a sigh of relief. Power down the Mac. Unplug power cable and wait at least 15 seconds. Plug the power cord back in. Now hold down these four keys simultaneously; Left Shift +Option + Control + Power Button for at least 10 seconds. Release all the keys and power that baby back up like a regular start.
SMC Reset on iMac, Mac Pro, Mac Mini or Xserve:
Power down the Mac and Unplug power cable, wait at least 15 seconds. Plug the power cord back in and wait at least 5 seconds. Turn on your Mac.