As you can see from my signature I use NoScript and in theory it should make pages load faster as it isn't loading and running scripts.
Only when that script effects the actual page loading would it stop that loading, which is rather different slowing page loading, if it loads completely but slowly then there is something else in the mix.
I don't see this impact with NoScript and it doesn't take long for those sites that you visit regularly and have allowed only the essential scripts to run, it doesn't become so intrusive.