Fletcher Previn could be one of the funniest IBM vice presidents the company employs.

Before achieving what he jokes as his “true life-long ambition of middle management at IBM” he worked as an intern on the “Late Show with David Letterman” and did a stint for Conan O’Brian, too, he told attendees at the Jamf tech conference.

When a career in entertainment didn’t work out, he made a nice living for himself as an IT pro managing fleets of Windows PCs for huge corporations.

Last year, he became a cult figure of sorts in the world of enterprise IT. As IBM’s VP of Workplace as a Service, Previn is the guy responsible for turning IBM (the company that invented the PC) into an Apple Mac house.

Previn gave a great presentation at last year’s Jamf tech conference where he said Macs were less expensive to support than Windows. (Jamf is a company that makes software that manage fleets of Macs and iOS devices.) Only 5% of IBM’s Mac employees needed help desk support versus 40% of PC users.

At that time, some 30,000 IBM employees were using Macs. Today 90,000 of them are, he said. And IBM ultimately plans to distribute 150,000 to 200,000 Macs to workers, meaning about half of IBM's approximately 370,000 employees will have Macs.

Previn's team is responsible for all the company's PCs, not just the Macs. All told IBM's IT department supports about 604,000 laptops between employees and its 100,000+ contractors. Most of them are Windows machines - 442,000 - while 90,000 are Macs and 72,000 are Linux PCs. IBM is adding about 1,300 Macs a week, Previn said.

With another year of working with Macs under his belt, he gave another funny presentation at Jamf's conference.

He reiterated that Mac users need less help. Although Macs make up about 15% of the PCs in use, only 5% of the help desk is dedicated to supporting them.

Previn says that while a Mac initially costs anywhere from $117 to $454 more than a similarly configured Windows PC, over four years IBM saves between $273 to $543 per Mac compared to a similarly configured Windows PC.

In other words, when you add in all the software a company has to buy from Microsoft to run and manage its Windows devices, Windows PCs are 3 times more expensive, he says.

"It ends up being $57.3 million more expensive per 100,000 Windows machines, or exactly 3X the cost," he said. "And this is a conservative number. This represents the best pricing we've ever gotten from Microsoft."

On top of that, employees have been downright glowing about the IT team since they began delivering Macs. Employees report a 91% satisfaction rating for their Macs. People are so happy that IBM's Japan unit declared it "would standardize on Macs, and make PCs the exception," Previn says.

By the way, IBMers also tend to prefer iPhones and iPads. 65% of the mobile devices they use run iOS, while 33% run Android, and there's a handful of Blackberry holdouts.

"The challenge is, all the people that still have Blackberries can fire me, so it's hard to force it from them," he joked.

Ultimately, he says this whole Mac experiment proves that when it comes to technology "If you make it simple and easy for people to use, they will pull it from you, you don't have to push it on them."

Here's the full keynote. Previn's presentation is the first 56 minutes.