<Thorns> there is a point where cass can't kill things anymore
http://www.youtube.com/watch?v=gvdf5n-zI14
Builds chosen for ease of comparison: Ashe has average base AS for an AD carry and no steroid. Cassiopeia is straight-up glass cannon though she will usually have a Rylai's or something. The difference between measuring spell range and autoattack range gives them approximately the same max attack range. Amusingly, they also both have stuns as ultimates.
Ashe - standard AD 21/9/0
Berserker's Greaves, Infinity Edge, Phantom Dancer, Last Whisper, Vampiric Scepter - 10335 gold
.658 base AS + (.658*.0334*17) + (.658*.84) =
1.584 attack speed
46.3 + 2.85*18 + 80 + 40 + 3 + .5*18 =
229.6 attack damage
25 + 30 =
55% critical strike chance for 260% damage
THE DEEPS
229.6*.45 + 229.6*.55*2.6 = 431.65 average damage per attack * 1.584 attacks per second =
683.73 damage per second
Less Armor, with 6 + 46% armor penetration, and 13% lifesteal. Rune setup will vary.
Cassiopeia - standard AP 21/9/0
Sorcerer's Shoes, Rabadon's Deathcap, Void Staff, Hextech Revolver, Needlessly Large Rod - 9795 gold
(330 AP itemized + 21
[Blast + 3/4 Mental Force]) * 1.35 =
473.85 AP
THE DEEPS
Noxious Blast = 78 + 473.85*.266~ = 204.36 * 1.015 (Havoc) = 207.4254 DPS
Twin Fang at one cast per second (e.g. hitting a poisoned target at range) = (190 + 473.85*.55)*1.015 = 457.3767625 DPS
Total combined 664.80 damage per second
Less MR, with 20 + 46% magic penetration, and 12% spell vamp. Rune setup will vary.
tl;dr Cass does the fucking deeps