100 int gives u like.... 1k more dps... which is nothing
Don't forget that int gives resist all (don't have the numbers handy, though, so can't translate 300 int to resist all).
Also, you might have awesome gear, but not all of us do, and a 3k dps increase (before force weapon/familiar) is not negligible for everyone
Int doesn't DR, it is in the same boat as attack speed, and weapon damage the more damage you have from other sources (wep dmg, crit, int, ias) the better it becomes.
Crit Chance and Crit damage are a bit different and can become more valuable the more you have of the other one. (with 200% crit dmg, crit chance becomes twice as valuable than if you had 100% crit dmg).
What you may be seeing, is 100 int when you have 0 int, and 1k base dps results in a 1k dps increase (100% extra dmg), but when you have 1000 int and the same 1k base dps, a 1k int results in a 1k extra dmg to 11k dmg (1100% extra dmg), note it was only a increase of 10% from the previous 10k dps, but the amount of dps it added was the same.
I'm using base damage to refer to your damage not including the effects of int.
Doesn't seem alot compared to how much 100k is. And it doesn't seem like adding just another 100 int to an already big int pool would do much... say compared to crit dmg.. crit chance or both.
I have 8% crit from gear, no crit dmg and about 30% ias (so kinda bad). That helm adds about 5-6k dps for me. The % dmg you gain from int is largely dependant on your wep. Low dps = you gain less. My wep is 800 dps with some +dmg from source and amulet. 300% dmg on that + ias and crit. Whats your wep dmg, source dmg, ias and crit ? how much would your ias + crit boost a 3k dmg ? 6k ?8k ?
Find a 100 int item. Empty the slot it goes in. Check the dps gain when you equip it.
With no ias or crit, int does have 'diminishing' returns in the way of total dps increase is such a small percentage when your dps is already high. But the more ias/crit you have, the better int actually gets.
That's a pretty wicked hat and short of a similar hat with crit, it is far higher dps than any rare hat I've seen. About the only hats better are the Visage legendary with Int. Based on my current gear it's equivalent to a visage with 90 int, 3 crit and 12 IAS. It's bound to be priced in the millions, but hopefully you already knew that.