A blank orange screen is not normal behavior you could have tried enabling the compatibility mode, caching https requests independently, many more things. I also don’t want to be the one to point this out I hope you are not actually using those 4 plugins..
While using Google Libraries is a semi great idea it has problems. Notably you can’t combine he JS with most plugins and serving one file from Google for the sake of caching is a waste.
DB Database Cache is as far as I can tell serving database queries from disk which you should never do unless you are running a strong ssd as it can slow the website down even more and use even more of your resources.
Super Cache is a great alternative, but I am not sure what your website needs.
Widget Cache.. This one is essentially useless as a static page is enough for most websites.
Its hard to say as I don’t know every thing about the site as I am not the one working on it but using those additional plugins really wont help your load time that much.
