Small question about Player Stat staff

Basic Mage Stat Staff is usually IM10,I20,CSPD20 or IMD10, I15(more or less).
I wonder about the Castspeed part since I am slowly shifting towards a burst mage build.

I was wondering which has better effects on Cast Speed?
Dex+10%
or
CSPD=20%

Thanks in Advance

 

So I used Coryn's Statting Calculator with level cap 210 stats, so that's 300 int and 247 dex, using only a staff with no other gear, and no xtals.
With IM10,I20,CSPD20, it's an estimated 1124. With IMD10, I15, it's an estimated 1007. No matter how I see it, CSPD% is much better at increasing your cast speed than Dex%, by approximately 0.117x. With 500 dex in the future, CSPD 20% still seems to have the upper hand on increasing cast speed than Dex%.

 

dex% only raises dex, which adds 3 cspd each.

cspd% increases your base cspd, which not only includes dex, but also agi and character level.

that's why cspd% is more effective on cspd.
the advantage of dex% is that it also boost all other stats affected by dex.

 

I'd use the NPC version since it gives you 50% cspd with decent 7% matk and 7% int. It also have 30% physical resist which is somewhat good.

Of course for a burst mage, player stat elemental staff is better in term of damage

 

in terms of dmg, player statted still wins, but if u want more utility especially if ur a staff+shield mage, that npc stat works best thanks to p.resist 30%
and cspd% is much better too if ur somewhat using casting skills, aura buffs, etc.