I can swear I depleted an enemy casters Magica this morning. He was across a moat and him an I were exchanging bolts. At one point he just stood there taking it like a man.

Also, very annoyingly, Damage Magicka Regen, Damage, Ravage, Lingering, etc. Poisons don't really seem to do all that much, they continue blasting away with spells, no issue.

No the worst are the ones that keep dropping to a knee and then getting back up. Even after I've emptied about a kajillion bolts of Lighting into their bodies.

That isn't true. I fought a Dragon Priest at a Dragon Shrine who was wielding a staff of fireball. Being a destruction mage and taking nearly 30 minutes to kill him, he eventually ran out and starting resorting to other spells. When I looted the staff, there were no charges.

Silence is your friend.

Not all of the enemy mages are the same level as your character. You can't tell if you are on a console.

When they use Wards, you cast spells to "destroy" the ward and then quickly attack them. Don't use fire on fire mages, etc. They resist it.

Yes they do run out of mana, im archer class fighter and i use poisons to drain mana and they come runnin in with their dagger to die at my feet

Some enemies have infinite Magicka but most do not.

Uhh yes they do run out of magicka. When a mage boss pulls out a dagger and charges at you, it ran out of mana.

I haven't been too bothered by casters, but I've found a fun little work around for the ones that use ward. Since they're targeting me and when they use ward they arent simultaneously throwing other spells (that I've noticed anyway) I throw up a flame atronoch behind them and power up an offensive spell like I'm going to hurl it at them but I just keep it charged. They ward up in anticipation for my fireball, keep coming closer and I back away, while my atronoch just kills them. Kinf od funny to watch it all unfold.