Blue wrote:As Uthgard uses precise floating point calculations and 1ms granularity for casting time you won't see "breaking points" here. Every point invested in Dex will give you a slightly better casting time.

Also see:

Q: Would you please give more detail as to how dex affects a caster?
For instance, I understand that when I have my dex maxed I will cast 25% faster.
How does this work incrementally? And will a lurikeen be able to cast faster in the end than another race?
A: From a dex of 50 to a dex of 250, the formula lets you cast 1% faster for each ten points.
From a dex of 250 to the maximum possible (which as you know depends on your starting total),
your speed increases 1% for every twenty points.