40/0/21 spec's dont work alone, they need really good gear, and a good grp, they also need a full frost mage in the raid so they get 10% more crit with winters chill
ive never used frost in raiding, and in long fights (BT level) you'll go oom before long.
something like :
Talent Calculator - World of Warcraft
that might do well, i dont know what level of raiding your at.
you could always try something like
Talent Calculator - World of Warcraft
for me, ive always been fire (10/48/3) and more recently (2/48/11) even for al'ar as my guild has had enough DPS to make up for the mages dps being lower than normal.