Originally Posted by Elysianfield

Let's assume that someway, somehow, you managed to get a passive 20% haste on your gear, and that we're looking at a 5 minute fight. If you were to use the exact same cast sequence in your 20% haste gear as you did in your non haste gear, you'd go oom in about 3 minutes, 50 seconds (trying to account for the mana lost from regen and spriest); you'd have delivered roughly the same amount of damage but in a little less than four minutes instead of five.