In fact, the actor says delivering the sleuth's dazzling, lightning-fast speeches of deduction was more exhausting than any other role he has taken on.
Benedict confessed: "Every deduction is hard. It's always a painful process. There are all the details. It's like a stream of consciousness of incredibly condensed information.
"He just goes at 100 miles an hour and it's a huge speed to rush it out.
"It's just hard, it's hard graft ? there's no other word for it."
Benedict goes over and over the Sherlock script before filming to try to get the detective's warp-speed delivery right.
He smiles: "I practise at home, there is a lot of midnight oil burned."
It all leaves him jealous of co-star Martin Freeman, whose character, Holmes' sidekick Watson, has far more laidback speech pattern AND who can remember a script after reading it once.
He said: "I'm not saying Martin has an easy job because what he does is with scalpel precision and he works incredibly hard.
"But he has a photographic memory, he looks at the lines in the morning and it's learned, that's it.
"I can't. And if I fall behind or if I'm having difficulty getting something in, it's really hard. Hats off to him for putting up with me."
But the guys' efforts have paid off ? the much-loved BBC1 drama returned to screens on Sunday and triumphed in the ratings with an astonishing 9.6million viewers. That's two million up on the original 2010 Sherlock series.
The breakneck dialogue by writer Stephen Moffat was just one of the hurdles Benedict, Office star Martin and the rest of the cast had to cope with.
Filming on the three-part series in London in August had to be suspended for a whole day after rioters attacked the set on location.
Benedict revealed: "They picked up a bit of rigging and were hitting the side of the bowser, this fire engine-like machine.
"They thought it was some part of the establishment ? but it's actually just an old pump engine that spews out water to wet down streets or give a rain effect. I think it spooked people, and we had to cancel a day's filming until it all settled.
"I went home and watched London burn, which made me very angry.
"God knows I've been blessed, having come from a privileged background ? but for people to pull themselves out of those situations, work so hard and then have their neighbourhoods and livelihoods completely trampled on really upset me."
Filming scenes set in winter during the summer also proved tough for the Londoner, who also stars in the Steven Spielberg movie War Horse, which reaches UK cinemas next week.
Benedict, 35, recalled: "It's harder than films because in a way you are constrained by time and budget.
"You are playing winter when its summer so heat was a huge problem, all the time it was like 'F***ing hell', pulling coats off, running outside to get some fresh air, air conditioning units blowing in our eyeballs because it was absurdly hot.
"It's meant to be Christmas, Martin's got that beautiful woolly jumper on and I'm swishing around in a coat and scarf and its 38 degrees Celcius!" Then there was the whipping he underwent in Sunday's episode at the hands of a lesbian dominatrix played by Lara Pulver.
Benedict told TV Biz: "Lara went for it, it was really painful, I actually had welts on my arm.
"I don't know how people get pleasure out of that kind of thing, I genuinely don't. I know I was on a set but I did wonder, 'What is it that puts people in that mindset?'"
Ironically, Benedict had come from the set of the film Tinker Tailor Soldier Spy, where he played Peter Guillam in the thriller full of sexual secrets.
He said: "The secret sex lives, including my character's being a homosexual but playing someone incredibly straight in the workplace ? there is that element in that world.
"I sort of understand the psychology but, thankfully, I also don't have that appetite or that need. I've had my moment with it!"
Benedict ? who stripped naked in a stage production of Frankenstein last year ? was also impressed by Lara's nerve in a scene when she had to go completely starkers.
He said: "It wasn't the first scene we did, thank God, but she just went for it. It takes someone to have real chutzpah to go ahead and do that as an actress. I applaud that.
"It's a very brave thing to do. I don't know a single actress that is completely happy with their body, I don't know many women who are, or men that are. Maybe Peter Andre!"
Next Sunday's episode of the double Bafta-winning series is written by its co-creator Mark Gattis, of The League Of Gentlemen fame.
It retells with a modern twist one of Arthur Conan Doyle's most famous Sherlock stories ? the one featuring the Hound Of The Baskervilles.
The final part of the trilogy is based on The Final Problem ? and Benedict is tight-lipped on whether the detective will survive. Conan Doyle killed off the sleuth in the original tale but brought him back to life in a later story.
So whether the series will ? or can ? return for a third series is another unsolved mystery.
Benedict said of the hit: "It's been fantastic, the variety of work and the people that I have got to meet.
"I'm sure it will keep going ? you saw the affection it holds, that was insane. It will be buoyed up by that.
"But where we will take it next, whether we can after what happens at the end of the next series, who knows?"Benedict's parents are also actors. His mum, Wanda Ventham, played Cassandra's mother in Only Fools And Horses. Dad Timothy Carlton was in sitcoms including Next Of Kin. He spent a gap year teaching English in a Tibetan monastery. Benedict dated Thick Of It actress Olivia Poulet for ten years before they split up last March. He is now seeing designer Anna Jones. The shy actor gets around on a moped with a helmet to avoid being recognised near his home in Hampstead, north London. He is the voice of dragon Smaug in Peter Jackson's upcoming film The Hobbit, in which Martin Freeman stars as Bilbo Baggins.