Are they just called "Bandit", or are you fighting a swarm of bandit cheifes or something? Because you should be able to tear through normal bandits like a hot knife through FLESH
I do, I tear through anything like they were nothing. I've dealt with Bandit Mauraders, all the varients, and I can literally do a power move and they die. The big jump from "oh, this game is easy, I'm killing everything" to "OH JESUS, IT'S LIKE I'M AN ANTHRITIC WEEVIL IN A BOXING MATCH WITH GOD" is what threw me.
I now think the campanion questline, if done too late, has a level-scaling bug which makes them unreasonably strong. Most people (inluding myself when I first played) probably do the companion quests early, if at all.
And they're a mixture of a chief, mauraders, and whatever the others are. There aren't any regular "bandits" as in "the 1-hit-even-at-low-level" variety though. They're all supermen.