From what I remember, those were just regular zombies. No Super Mutant Zombies. And the vampires were setted to be x6 stronger than a peak human.
I vaguely remember them taking a heavyweight lifter champion, measured his punch and multiplied it by 6. The vampires ended being capable of punching things with the force of over 1 ton. They were mostly one-shotting the zombies but due to the zombies being too many... well...