Each hero has a different AS per second (1.5, 1.4 and etc) AM and Jugg are the heroes that have the highest AS per second (1.1) and they will benefit from the red shard the most. Abilities like Chemical Rage will give you 1.0 on any hero while active. But (!) it won't work with a red shard. Keep this in mind. If your base AS per second is 1.5 and you'll take a melee skill of troll then you'll gain a bonus to your AS (since this skill gives 1.4 when active) So it will be lower than 1.4

still complicate to me but thanx a lot!! I'll be try to figure out on arena

to explain in a way you will maybe understand better. what this guy say is AM and jug with highest AS per second (1.1). I see in the game when reach max(before swallow dark moonshard) your attack speed value will be 850 attack speed

This also mean if you use chemical rage(but not swallow dark moonshard) on am or jug your attack speed will be somewhere around 1100

If swallow dark moonshard and you buy more attack speed to max, most heroes max will be 909 attack speed

oooh!! ok ok, so If I have chem rage I shouldn't use dark moon shard to reach the max AS!! interesting

now let's see, what if I pick Alchemist, troll's berseker's rage, -0.1 chem rage's talent, chem rage and reach to max flat AS? or how I could get the most fastest AS in the game?

AS modification skills do not stack with each other. At least it's not working properly. So I don't recommend having Chemical Rage and Berserker's rage at the same time.

yup, berseker rage overwrite the chem rage, even de dark moon shard, it doesn't work