Assuming you dont have any other source of IAS anywhere else, 125IAS is needed for the 9 Frame.

So if I were to get a Fury of chaos Greater Talon I would only need 42 ias correct? and 125ias for Suwayyah

Correct. 42IAS is needed for 9 frame if you have 40IAS on Greater Talon.

This post was edited by RenTed on Oct 15 2018 02:51pm

9 FPA is given by 61% EIAS, which is 125% item-ias from all sources weapon/non-weapon. But if you have for example +45% EIAS from level 10 burst of speed, you'd only need 16% more EIAS, which is only 19% item-IAS.
calculating how much IAS you need without an attack speed calculator like titanseal's is not too difficult, consult this chart;
https://www.theamazonbasin.com/wiki/index.php/Attack_speed

if you have a -30 base like greater talons, you only need 61-30 = 31% EIAS, and per the chart that's given by 42% item-ias; floor((120 * 42) / (120 + 42)) = 31

as per that link, EIAS gets a lot more complicated if you want to WSM bug

This post was edited by Goomshill on Oct 15 2018 03:38pm

Sent to both ty for the answers