Lexmark claims a top speed of 43ppm for the T650dn and on a 20-sheet document we achieved 34ppm, closer than we often get with our real-world tests. We saw this on both a text document of 20 different pages and on a job producing 20 copies of a single text and graphics page.
Although, as we've said, a duplexer is a slightly cumbersome accessory for this printer, it has the advantage of not slowing down two-sided print jobs by as much as machines which handle duplexing internally. A 10-page, 20-side text document took 44 seconds to print, giving a speed of 27.3ppm, a pretty good result which should mean a lot of departments can make paper savings - and help the environment - by making duplex print a default.
The printer has a standard resolution of 1,200dpi and this shows in the quality of text print which is sharp and dense, giving a very professional appearance. Greyscale graphics, common in business documents, are reasonably well reproduced, though there's some banding apparent in areas of grey. Black text over greyscale fill looks reasonable, though, and for many internal & external documents, will be more than adequate.
Our photo test print at the enhanced, pseudo-2400dpi top resolution of the machine still showed some banding in smooth areas of fill and lost quite a bit of detail in areas of shadow. Photo reproduction isn't any mono laser's strong suit, but print here is no better than average.
There are two capacities of toner cartridge available for the T650dn: 7,000 pages and 25,000 pages and it's far more economic to buy the larger capacity cartridge. Lexmark's Return Programme cartridges are slightly cheaper than the standard ones, as long as you undertake to return the cartridges to the company. We've used the high yield version of this cartridge in our page cost calculations.
Working through the arithmetic gives a cost per page of 1.88p. This is a good cost, though we've seen slightly lower with, for example, Dell's 2335dn returning 1.70p.
Lexmark's T650dn does pretty well on all three of the key criteria and really excels at expandability. Unfortunately, you'll probably need to take advantage of that quite soon after purchase, as the 350-sheet main paper tray is inadequate for a machine in this category. It's print features are flexible, though, and we like the print hold and walk-up printing features, which gives the machine both versatility and security for medium or large workgroup use.