I think the site dice to roll the fastest is primedice. I use three gambling sites which of the three sites between bitsler. crypto games and primdice fastest is primedice. and often fail to roll is bitsler
I agree on PrimeDice, I think it is one of the fastest, but I wouldn't say it is always fast. Sometimes the bets are very slow and I know it has nothing to do with my internet speed, because folks in the chat are also complaining.
Also Fastdice was good, you could set autobet at 3+ bets per second there, but again it wasn't always that fast. Now it looks like the site had disappeared completely. They were promising to reopen but now I get this message "This Account has been suspended." on their page.