During the quarterly earnings call for Apple (AAPL.O) on Thursday, analysts were most interested in a product that has yet to be launched to the public.

The upcoming artificial intelligence system, Apple Intelligence, from Apple may spur a new round of iPhone upgrades and hardware sales. However, CEO Tim Cook and CFO Luca Maestri spent a lot of time in the Q&A section of the analyst call avoiding questions about Apple's promotional speed, whether or not the company has seen the service's promotional impact on sales, and the agreement with OpenAI to integrate ChatGPT into its software, among other questions.

One question Cook was willing to answer was about the company's spending on AI servers. This question has been asked throughout the tech earnings season as investors try to determine the company's progress in AI infrastructure construction and how much future investment there will be.

Cook acknowledged costs were rising during the earnings call.

"Our performance this quarter includes year-over-year growth in spending on AI and Apple Intelligence," Cook told CNBC's Steve Kovach on Thursday.

Apple reported property, plant, and equipment spending of $2.15 billion in June, up 8% from the previous month and about 3% from the previous year. Some of this capital investment was not used for AI but for other businesses of Apple's.

Compared to large-cap companies such as Microsoft (MSFT.O), Alphabet (GOOGL.O), and Meta Platforms (META.O), Apple's capital spending has barely increased. These companies are investing heavily in data centers with AI as the focus and equipping them with Nvidia chips.

For example, according to FactSet data, Microsoft's capital spending in the June quarter was $13.87 billion, up 55% year over year. Alphabet's spending surged 91% to $13.19 billion, and Meta's capital spending increased 31% to $8.3 billion for the quarter.

Meta CEO Mark Zuckerberg explained the reason for the surge in spending in game-theoretic terms. He said that the risk of missing out on the generative AI boom is greater than the disadvantage of overspending on graphics processors and servers. Zuckerberg also hopes to ensure that Apple does not control the next major technological change if it turns out to be AI.

"Actually, I think all the companies investing are making rational decisions," Zuckerberg said last week on a Bloomberg podcast. "Because the disadvantage of being behind is that you'll lose your position in the most important technology of the next 10-15 years."

Apple is playing a different game.

Unlike Amazon, Google, and Microsoft, Apple does not rent out infrastructure for cloud services to other companies. Meta also does not engage in this business, but Apple is investing in training its own open-source large language model and using AI to power its vast recommendation engine.

Apple revealed in a technical document this week that it had rented a relatively small amount of cheap Google TPUs, rather than Nvidia (NVDA.O) chips, to train its Apple Intelligence model. The company released the first version of its Apple Intelligence this week, which will improve Siri, generate emails and pictures, and categorize notifications. But it is currently only available for developer testing.

Apple's advantage in building infrastructure lies in the fact that it has designed its own chips for both smartphones and servers, so the company does not have to spend billions of dollars purchasing third-party processors.

Apple takes a "mixed" approach to data centers, shifting some capital spending to partners and turning them into operating expenses for Apple.

"Regarding capital expenditures, it's important to remember that we use a mixed approach where we investment internally, and we work with some external partners and the capital expenses will appear in their respective businesses," Cook said during the analyst call.

One of the partners is OpenAI, whose ChatGPT technology will be integrated into iOS later this year. OpenAI rents Nvidia GPUs from its main investor, Microsoft. Apple also rents cloud capacity from providers such as Amazon, Google, and Microsoft.

Apple refused to discuss details of the OpenAI agreement on Thursday, calling it confidential. But Cook said there may be monetization opportunities.