Can't disable by default on all websites

[g-i-o-r-g-i-o]

I've noticed a big performance degradation since I've installed noscript on firefox.

I'd like to enable noscript only on certain websites which have some annoying content, and completely disable it on all other websites.

I've tried to disable it by default, by enabling all options: general > Preset customization (for all the sites sharing a preset) > default > check all options but still the browser is quite slow (yet I've got a fast machine), when compared to a "private window" on firefox, or to a standard window on chrome (clean install, "noscript" not installed).

[mrx23dot]

I always wondered how to do proper profiling in firefox to see why pages load slow.