A fast startup on your system affects your system SSD, depending on how frequently you shut down your laptop, while a fast startup allows your system to be up and running faster after you shut down your laptop. At the same time, SSD is meant to transfer data at a very high speed; fast startup doesn't impact your system SSD like the Hard Disk, which tends to transfer data at a slower pace. In essence, a fast start-up will only have a damaging effect on the Hard Disk or slow down its performance than on the SSD.