People, especially IT professionals, enjoy arguing. Look no further than the comments posted to the article I wrote comparing the real-world cost of a MacBook Pro vs. a comparable Dell Latitude. You can present facts all day long, but you’ll still find reasonably educated people seeking to debate what, to many, already appears cut and dried.

Real-world desktop comparison

Let’s dig deeper by exploring the true cost differential between a Mac desktop and an equivalent Windows business-class all-in-one computer.

Apple’s entry-level desktop is the 21.5-inch iMac. The $1,299 (USD) computer includes a 2.7 GHz quad-core Intel Core i5 CPU, 8 GB RAM, a 1 TB hard disk, and Intel Iris Pro-powered graphics supporting 1920×1080 resolution. An HD camera is included within the all-in-one’s frame. Peripheral connectivity is supported via four USB 3 ports, two Thunderbolt ports, and a gigabit Ethernet port.

Finding an apples-to-apples comparison can prove to be difficult. Few Windows all-in-one business-grade computers measure up to the Apple in terms of display size or specifications. Dell, however, offers the OptiPlex 3011 all-in-one for $1,212.86 (USD), with promotional pricing lowering the cost to $849 (USD).

The Dell system offers potential. It includes Windows 7 Professional and an Intel Core i5 CPU. However, only 4 GB RAM and a 500 GB hard drive are included for that price. Unfortunately, at the time of this writing, Dell’s configuration tools didn’t offer the ability to upgrade the machine to match the Apple iMac’s build. Sourcing a 1 TB drive and an additional 4 GB of RAM could add $99 for the drive (at Newegg) and $44 for RAM (at Crucial). The Dell’s equivalent hardware cost, then, becomes $992 (USD).

However, that hardware total doesn’t factor necessary expenses, either in the form of a business’ in-house IT staff or an outside consultant’s time, to install the additional RAM and hard drive and reinstall Windows on the new disk, all of which likely voids the manufacturer’s limited hardware warranty. Those are real-world time, opportunity, and service costs businesses truly pay, but I won’t even try to estimate them here.

The price differential between the Dell and the Apple is $307, but unfortunately, there are still significant differences between the two systems. The Apple boasts a larger 21.5-inch display, integrated Bluetooth, and exponentially faster Thunderbolt connectivity.

Furthermore, few business desktops are used without office productivity apps. Apple’s Pages, Numbers and Keynote are natural choices for Apple businesses. Windows organizations naturally gravitate toward Microsoft Office. The Home and Business 2013 edition adds $219.99 (USD) for Windows companies, whereas Apple businesses pay only $59.97 (USD) for the Apple equivalent. The inclusion of office apps brings the totals to $1,358.97 (USD) for the iMac and $1,211.99 (USD) for the all-in-one Windows system.

Obviously, the cost to upgrade the Windows system to match the Apple iMac will result in the Windows system’s price exceeding that of the iMac. On top of that, Windows users are left with a machine that is likely out of warranty, possesses a smaller screen, has slower peripheral connectivity (due to the lack of integrated Thunderbolt ports), and runs an OS that’s growing less popular by the day. Don’t act surprised. In June, Gartner predicted that iOS/OS X will soon surpass Windows as the most popular computer platform.

Remember, too, that the day I priced the OptiPlex 3011, Dell was offering essentially a 30% discount as part of a promotional pricing campaign. Here’s hoping that, should you still not be convinced Apple computers’ total cost of ownership is much more competitive than Windows systems, the all-in-one Windows computer you buy is still on sale. Otherwise, you may find your firm paying hundreds of dollars more per unit for an inferior computer.