The company confirmed to CNET News.com that it has started offering machines that in some cases have improved processing powers and other enhancements. However, Apple is not labeling the new machines in any special way, so buyers have no way of knowing if they are getting the more capable models.
"Some Mac Mini systems may contain components that slightly exceed the published specifications," Apple said in a statement. "There are no changes to the published specifications or part numbers."
Apple would not confirm the exact specifications of the enhanced systems, but enthusiast site Think Secret said that some models were shipping with 1.5GHz processors, up from the current 1.42GHz, as well as a faster DVD burner, more video memory and improved Bluetooth wireless abilities.
Industry watchers were confounded by Apple's decision not to explicitly label the upgraded models.
"It doesn't make sense to me why they would do this," said Technology Business Research analyst Tim Deal, who added that Apple's tactic creates something akin to a "grab bag."
Stephen Baker, who follows the retail PC market for NPD Techworld, called the move "highly unusual," saying that meaningful changes to a computer's hardware specifications typically are designated by a new part number.
Not adding one could irritate some retailers and even cause headaches for Apple in its own retail stores, Baker said. Customers who end up with only the advertised specifications may decide to return their product, knowing that better models exist.
"Most retailers are pretty careful to make sure that what's on the box is what's inside and that the customer gets what they believe they are buying," Baker said. "It's a measure of trust. Whether it's better or worse isn't even necessarily the issue."
An Apple representative was not immediately able to say why the company decided to handle things as it has.
"I don't think you should mix the channel like that and not make people aware," Deal said. "If you are upgrading a product category, then traditionally you will offer some price discounting on the existing product to clear out the channel and then introduce the upgraded version with some amount of hype."
The Mac Mini is Apple's lowest-priced line of computers, with models ranging from $499 to $699. Apple last, adding faster processors and more memory.
In August, Apple announced a promotion that would allow customers toa Mac Mini for 30 days. However, the promotion was with no explanation.