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.
PrimeDice? Lol. Ok.
I'll go with Bitsler, when the site open for the first time I remember the roll was so slow and the server laggy, but now they have improved the site and roll goes so fast not only with the flash bets but automatic betting too.