Regarding the page file. The best advice is to set a page file on each physical drive and set each to Windows controlled. Advice on websites telling you to set the page file to a fixed size or even to turn it off should be ignored. The windows memory manager knows best how to manage its memory and can do so optimally if left to do its own thing.

With a page file on each physical drive it will use whichever has least I/O on it.

With regards superfetch, you'll gain nothing by turning it off. It runs low priority and will only make use of memory for caching whilst that memory is not needed for anything else. If it is then it simply drops memory pages without issue for use by the programs requiring it.