About how Dex works

Hi guys. I'm playing a EP4 server and building an assassin/ranger. So i hear about it: dex only works up to 600 points. So i would like to know if thats true, if don't which is this value?because im building full dex and dont want to waste any points. I would appreciate if ypu help me thank you.
( You can also give me better assassin's/ranger stats if you like to)

I recommend you play STR based. If you're playing with almost original client 350-500 dex should be enough. You could deal some serious damage in pvp and also in 1v1. Sure, you'd die easily at the field but if you don't wanna die at all, might as well just go full rec&wis and walk around like a useless. And dex also works different for each server, i don't know the details but there are so many settings in dex values. So you can't know the exact value for the server you play at. Mostly those values are just myths. Don't believe them.

And also seing 8-12 k critical hits in the pvp field is sooo fucking satisfying..

As i said, is an ep4 server. So if i'm an assassin and dont put a lot of dex i will die to 1 deadly strike. 350-500dex is good enough to other classes like hunter/archer, warrior/fighter because they wont die so easily. But assassin's defense is Dex and thats why i wanna know a good value to still alive in pvp. (Playing shaiya Lands)