I vetted this over on EQ forums, so I think it is correct.
This should tell you what effects stack and what don't
My buff effect stacking rules
Damage Bonus (similar to the damage bonus you see on weaps and Faycite shards):
inc to damage bonuses stack, but they are not affected by inc % to melee damage
damage bonus does not affect crits.
crits are based on base damage of spells and melee, with bonus applied afterwards
Increase to non-Crit damage:
inc % to melee damage does NOT stack
inc % to DD spell damage does NOT stack
inc % to DoT spell damage does NOT stack
Increase to Crit chance:
inc melee crit chance does NOT stack
inc DD spell crit chance stacks
inc DoT spell crit chance stacks
Increase to Crit damage:
inc % to melee crit damage stacks
inc % to DD spell crit damage does NOT stack
inc % to DoT spell crit damage stacks
Incease chance to hit:
inc chance to hit does NOT stack
Incease to accuracy:
inc accuracy do stack
Increase to haste:
Item haste do NOT stack
Spell haste (V1) do NOT stack
Spell haste songs (V2) do NOT stack
Overhaste (V3) do NOT stack
Item + V1 + V2 capped at 100%
Item + V1 + V2 + V3 capped at 125%
Weapon delay reduction:
100 hands (weapon delay reduction) does not stack
Separate damage shields:
Some DS stack, but DS is really its own category
Damage shield increases:
DS increases do stack
Other effects:
HP increases are cumalative
Atk increases are cumalitive
AC increases are cumalative
Resist increases are cumalative
