No matter what browser I use I always get slow down with some tabs. Especially with Queen tabs because of loads of instruments being used. 
Seems to be worst the more instruments being used too me. 
Official and Pro tabs don't load no matter what browser you use. Did get a script error if I waited long enough.  Two days now and no official word as yet....
Same thing here. Not a browser issue but rather a UG issue, like always.
Same issues here. reason why I use Guitar Pro these days...