the attack speed cap has effectively been removed.
so, explanation.
in original diablo 2 and it’s expansion, attack speed was linked to the number of frames rendered in the game. the framerate was locked, because casting speed, attack speed, and run speed and damage tics were tied to the number of frames rendered per second.
it wasn’t a problem because PC hardware wasn’t as capable as it is today, computers weren’t made with monstrous processors that could change clock speed on the fly, boost their speed by upwards of 50% and then slow down to save power when not under load. the cpu just ran at whatever frequency it was made to run at, and that was what you got.
so a lot of games based their timing and mechanics around that kind of hardware.
so, in original diablo 2, when you clicked on an enemy to attack, if you were in range to do that attack, the character would perform the animation of the attack
“attack speed” was the number of rendered frames it took to perform the attack animation, with the damage being calculated when the animation concluded.
“X% increased attack speed” on gear reduced this number of frames required for the animation, and there was a hard cap on it. this hard cap meant you could not go below something like 5 frames per attack animation. when the original game was released, the game was locked at like 30 frames per second or so, i’m not sure what the exact was. but it equaled out to about 2.7 attacks per second as the maximum possible increased attack speed.
it was a hardware limitation, not a software one.
now, when they updated the game to work on modern computer hardware and operating systems, that limitation is gone, so increased attack speed seems broken. you can now stack IAS to ridiculous numbers, getting close to one attack per rendered “frame”, which is how these streamers are showing amazons looking like their bows fire like a gatlin gun