Frostbolt cast time in PvP

[Valkur]

For a little while now i have been noticing that most of the time that when i start a fight in BG's or arena's, and there is a mage involved, that the first frostbolt that they cast, they cast it in less then a second (or a lot faster than usual). Its not that i am bitching about it, i just want to know how they do it! I dont know if its because maybe my computer is lagging a bit at the very begining, or if the more really skilled mages have figured out a trick that makes them get a really quick head start with that move.

It seems to happen alot in arena's, not too much BG's. So if anyone has any clue on how they do it and would like to say why (or even if you have an idea about it and would like to say it) please feel free to do so.

[Deleted]

I would assume they're using rank 1 frostbolt. This still has the same chill effects as the highest rank but because of the quick cast time is a lot easier to open with and get a debuff up on the target.

[RGeneral24]

rk1 frostbolt has many uses:
opener for debuffs
dispell protection if u sheep / deep the target
snare forcing aka keep that feral drood snared while shapeshifting forcing another gcd
snare the passing guy on the horse
prevent that pesky rogue from fleeing
trying crits on the boars on durotar (forcing a ttw)

too bad we will loose the rks in cata but u'll have early frost so i dont mind :P