I haven't seen that msg on Win7 x64, ever. Neither on Win8 nor Win8.1. I use 8.1 on a daily basis. Anyway, some say in other forum, no harm at all or negative side-effects.
Realy...do you have system without any running processes? I think you should try look into some menagers of processes with write/read disk analyzer and perhaps you can find some processes touched by SD because there are some disk operations that we can't see on our own eyes.