In D2Lod it's pretty easy. 34% IAS is required to hit 4 frame (fastest breakpoint) with Berserker Axe
D2r is more complicated, IAS from any source can now affect WW. Skills, wep and armor. The only thing that doesn't count is your offhand %IAS when your main hand is swung and vice versa. IAS from skill also has a stronger effect as it's not effected by diminishing returns.
To simplify for BA:
14% IAS total to hit 4 frame attack with lvl9 fant from beast
63% IAS without any fant.
So if you are running classic griefz/beastz any IAS roll will work on grief.
As mentioned %slow, decrep and cold now slow u down in ww:
With 10% slow:
Lvl9 fant 27%
Bo fant 89%
Decrep or chilled essentially fuck ww and u will need 150+ to get back to 4frame
Thank you for this, very clear (ww)
What about IAS required for zerk ?