(at the end of the blur pass it prints the elapsed time to the console)
You're right, it does get kind of slow at 2x, but not that slow, on my laptop it takes around 1 sec/page, while on your site takes 20-30 secs/page. Also, my very naive code does not take into account "warming up" and some other code optimizations to make the blur much faster, you could easily get it down to 100ms/page, I'm sure!
https://codepen.io/almosnow/pen/abEXBZP?editors=0011
(at the end of the blur pass it prints the elapsed time to the console)
You're right, it does get kind of slow at 2x, but not that slow, on my laptop it takes around 1 sec/page, while on your site takes 20-30 secs/page. Also, my very naive code does not take into account "warming up" and some other code optimizations to make the blur much faster, you could easily get it down to 100ms/page, I'm sure!
Best luck!