A. Superfetch is a great feature that preloads programs into memory. When the user launches the programs, they start faster than normal. However, if you have an SSD drive, random reads are very fast. So does Superfetch help or just cause more I/O hit to the SSD, decreasing its lifetime?
You can manually disable the Superfetch service by disabling it, but Windows 7 actually takes care of this for you. Supefetch checks the WinSAT disk score of the system (which considers random reads and writes) and if it’s over 6.5, Superfetch automatically turns itself off.
Defrag performs a similar check and doesn't run if the device doesn't have a seek penalty--it checks
IOCTL_STORAGE_QUERY_PROPERTY:StorageDeviceSeekPenaltyProperty
If the system can't figure that out, it won't run defrag if your disk's random read rate is greater than 8MB/second.
