"The Sardaukar are excellent fighting men, no doubt of it," the Baron said. "But I think my own legions — "
"A pack of holiday excursionists by comparison!" Hawat snarled. "You think I don't know why the Emperor turned against House Atreides?"
[...]
The Baron rubbed his jowls. "Well, he has been recruiting rather heavily, to be sure. His agents make rather extravagant promises and — "
"Shall we say thirty thousand in round numbers?" Hawat asked.
"That would seem a little high," the baron said.
"Quite the contrary," Hawat said. "I can read between the lines of Rabban ' s reports as well as you can. And you certainly must've understood my reports from our agents . "
"Arrakis is a fierce planet," the Baron said. "Storm losses can — " "We both know the figure for storm accretion," Hawat said. "What if he has lost thirty thousand?" the Baron demanded, and blood darkened his face.
"By your own count," Hawat said, "he killed fifteen thousand over two years while losing twice that number. You say the Sardaukar accounted for another twenty thousand, possibly a few more. And I've seen the transportation manifests for their return from Arrakis. If they killed twenty thousand, they lost almost five for one. Why won't you face these figures, Baron, and understand what they mean? "
By all accounts, reinforced both by the Fremen themselves and by Hawat in this scene, the Sardaukar are much better soldiers/fighters than the Harkonnen troops (and indeed, anyone at the time, expect the Fremen and a small elite force of the Atreides). Yet Hawat seems to indicate that during their campaign against the Fremen they pulled a much worse casualty ratio (5:1) than the Harkonnen troops directed by Rabban. (2:1)
How is this possible considering that Rabban is not quite a genius, and that during the two years considered here the power and knowledge of Muad'Dib was spreading and making the Fremen even more adept in warfare?